{"id":1621,"date":"2021-03-21T21:53:07","date_gmt":"2021-03-21T13:53:07","guid":{"rendered":"https:\/\/jimmyswebnote.com\/?p=1621"},"modified":"2021-03-21T21:56:34","modified_gmt":"2021-03-21T13:56:34","slug":"javascript-sync-async","status":"publish","type":"post","link":"https:\/\/jimmyswebnote.com\/javascript-sync-async\/","title":{"rendered":"JavaScript \u4e2d\u7684\u540c\u6b65\u8207\u975e\u540c\u6b65 &#8211; Event Loop \u539f\u7406"},"content":{"rendered":"\n<p>\u525b\u597d\u6700\u8fd1\u516c\u53f8\u8b80\u66f8\u6703\u5831\u544a\u5230\u9019\u500b\u4e3b\u984c\uff0c\u5c31\u9806\u624b\u628a JavaScript \u4e2d\u7684\u540c\u6b65\u8207\u975e\u540c\u6b65\u6574\u7406\u6210\u6587\u7ae0\u4e86\u3002<\/p>\n\n\n\n<p>\u5728\u8aaa\u660e\u540c\u6b65\u8207\u975e\u540c\u6b65\u7684\u6982\u5ff5\u4e4b\u524d\uff0c\u5148\u7c21\u55ae\u4ecb\u7d39\u4e00\u4e0b JavaScript \u9019\u500b\u7a0b\u5f0f\u8a9e\u8a00\u3002<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_65 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-663357b72f844\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-663357b72f844\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#1_JavaScript_%E7%9A%84%E7%89%B9%E6%80%A7\" title=\"1. JavaScript \u7684\u7279\u6027\">1. JavaScript \u7684\u7279\u6027<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#11_%E9%9C%80%E8%A6%81_JavaScript_%E5%BC%95%E6%93%8E%E6%89%8D%E8%83%BD%E5%9F%B7%E8%A1%8C\" title=\"1.1 \u9700\u8981 JavaScript \u5f15\u64ce\u624d\u80fd\u57f7\u884c\">1.1 \u9700\u8981 JavaScript \u5f15\u64ce\u624d\u80fd\u57f7\u884c<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#12_%E5%96%AE%E5%9F%B7%E8%A1%8C%E7%B7%92_Single_Thread\" title=\"1.2 \u55ae\u57f7\u884c\u7dd2 (Single Thread)\">1.2 \u55ae\u57f7\u884c\u7dd2 (Single Thread)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#2_%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C_JavaScript_%E7%9A%84%E7%BC%BA%E9%BB%9E\" title=\"2. \u540c\u6b65\u57f7\u884c JavaScript \u7684\u7f3a\u9ede\">2. \u540c\u6b65\u57f7\u884c JavaScript \u7684\u7f3a\u9ede<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#21_%E9%98%BB%E5%A1%9E_block_%E5%BE%8C%E9%9D%A2%E7%A8%8B%E5%BC%8F%E7%A2%BC%E7%9A%84%E5%9F%B7%E8%A1%8C\" title=\"2.1 \u963b\u585e (block) \u5f8c\u9762\u7a0b\u5f0f\u78bc\u7684\u57f7\u884c\">2.1 \u963b\u585e (block) \u5f8c\u9762\u7a0b\u5f0f\u78bc\u7684\u57f7\u884c<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#22_%E5%9C%A8%E7%80%8F%E8%A6%BD%E5%99%A8%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E6%99%82%EF%BC%8C%E6%9C%83%E9%98%BB%E5%A1%9E%E7%95%AB%E9%9D%A2%E7%9A%84%E6%B8%B2%E6%9F%93render\" title=\"2.2 \u5728\u700f\u89bd\u5668\u540c\u6b65\u57f7\u884c\u6642\uff0c\u6703\u963b\u585e\u756b\u9762\u7684\u6e32\u67d3(render)\">2.2 \u5728\u700f\u89bd\u5668\u540c\u6b65\u57f7\u884c\u6642\uff0c\u6703\u963b\u585e\u756b\u9762\u7684\u6e32\u67d3(render)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#23_%E8%A7%A3%E6%B1%BA%E7%80%8F%E8%A6%BD%E5%99%A8%E4%B8%AD%E9%98%BB%E5%A1%9E%E6%B8%B2%E6%9F%93%E7%9A%84%E5%95%8F%E9%A1%8C_%E2%80%93_Web_Worker\" title=\"2.3 \u89e3\u6c7a\u700f\u89bd\u5668\u4e2d\u963b\u585e\u6e32\u67d3\u7684\u554f\u984c &#8211; Web Worker\">2.3 \u89e3\u6c7a\u700f\u89bd\u5668\u4e2d\u963b\u585e\u6e32\u67d3\u7684\u554f\u984c &#8211; Web Worker<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#3_JavaScript_%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E5%8E%9F%E7%90%86_%E2%80%93_Call_Stack_%E7%9A%84%E8%A7%80%E5%BF%B5\" title=\"3. JavaScript \u540c\u6b65\u57f7\u884c\u539f\u7406 &#8211; Call Stack \u7684\u89c0\u5ff5\">3. JavaScript \u540c\u6b65\u57f7\u884c\u539f\u7406 &#8211; Call Stack \u7684\u89c0\u5ff5<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#4_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C\" title=\"4. JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\">4. JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#41_%E7%82%BA%E7%94%9A%E9%BA%BC%E9%9C%80%E8%A6%81%E9%9D%9E%E5%90%8C%E6%AD%A5%EF%BC%9F\" title=\"4.1 \u70ba\u751a\u9ebc\u9700\u8981\u975e\u540c\u6b65\uff1f\">4.1 \u70ba\u751a\u9ebc\u9700\u8981\u975e\u540c\u6b65\uff1f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#42_%E7%82%BA%E7%94%9A%E9%BA%BC%E7%80%8F%E8%A6%BD%E5%99%A8%E5%8F%AF%E4%BB%A5%E5%AF%A6%E7%8F%BE_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%EF%BC%9F\" title=\"4.2 \u70ba\u751a\u9ebc\u700f\u89bd\u5668\u53ef\u4ee5\u5be6\u73fe JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\uff1f\">4.2 \u70ba\u751a\u9ebc\u700f\u89bd\u5668\u53ef\u4ee5\u5be6\u73fe JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\uff1f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#43_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E5%8E%9F%E7%90%86\" title=\"4.3 JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\u539f\u7406\">4.3 JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\u539f\u7406<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/jimmyswebnote.com\/javascript-sync-async\/#5_%E5%8F%83%E8%80%83%E8%B3%87%E6%96%99\" title=\"5. \u53c3\u8003\u8cc7\u6599\">5. \u53c3\u8003\u8cc7\u6599<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"1_JavaScript_%E7%9A%84%E7%89%B9%E6%80%A7\"><\/span>1. JavaScript \u7684\u7279\u6027<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"11_%E9%9C%80%E8%A6%81_JavaScript_%E5%BC%95%E6%93%8E%E6%89%8D%E8%83%BD%E5%9F%B7%E8%A1%8C\"><\/span>1.1 \u9700\u8981 JavaScript \u5f15\u64ce\u624d\u80fd\u57f7\u884c<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6211\u5011\u90fd\u77e5\u9053 JavaScript \u662f\u4e00\u500b\u7a0b\u5f0f\u8a9e\u8a00\uff0c\u7136\u800c\u8981\u57f7\u884c\u9019\u500b\u7a0b\u5f0f\u8a9e\u8a00\u9700\u8981\u6709 JavaScript \u5f15\u64ce\u624d\u80fd\u7de8\u8b6f\u4e26\u57f7\u884c\uff0c\u6700\u6709\u540d\u7684 JavaScript \u5f15\u64ce\u5c31\u662f Google \u6240\u958b\u767c\u7684 V8 \u5f15\u64ce\uff0c\u88ab\u7528\u5728 Chrome \u700f\u89bd\u5668\u9084\u6709 Node.js \u4e0a\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-engine.jpeg\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-engine.jpeg\" alt=\"JavaScript \u5f15\u64ce\" class=\"wp-image-1622\" width=\"638\" height=\"479\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-engine.jpeg 638w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-engine-300x225.jpeg 300w\" sizes=\"(max-width: 638px) 100vw, 638px\" \/><\/a><figcaption>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/medium.com\/@paulyang1234\/%E9%80%B2%E9%9A%8E-javasctipt-%E6%A6%82%E5%BF%B5-1-e1a175502db9\" target=\"_blank\" aria-label=\"\u9032\u968e Javasctipt \u6982\u5ff5 (1) (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">\u9032\u968e Javasctipt \u6982\u5ff5 (1)<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"12_%E5%96%AE%E5%9F%B7%E8%A1%8C%E7%B7%92_Single_Thread\"><\/span>1.2 \u55ae\u57f7\u884c\u7dd2 (Single Thread)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u4e0a\u8ff0\u6240\u63d0\u5230\u7684 JavaScript \u5f15\u64ce\uff0c\u662f\u4f7f\u7528\u55ae\u57f7\u884c\u7dd2 (Single thread) \u4f86\u57f7\u884c JavaScript \u7684\uff0c\u4e5f\u5c31\u662f\u8aaa\uff0c\u6bcf\u6b21\u57f7\u884c JavaScript \u6642\u53ea\u6703\u57f7\u884c\u4e00\u5c0f\u6bb5\u7a0b\u5f0f\u78bc\u7247\u6bb5(\u6700\u5e38\u898b\u7684\u55ae\u4f4d\u70ba function)\uff0c\u8b1b\u767d\u8a71\u4e00\u9ede\u4e5f\u5c31\u662f\uff1aJavaScript \u57f7\u884c\u6642\uff0c\u4e00\u6b21\u53ea\u80fd\u505a\u4e00\u4ef6\u4e8b\uff0c\u6240\u4ee5\u5728\u57f7\u884c JavaScript \u7684\u6642\u5019\uff0c\u662f\u5c6c\u65bc\u540c\u6b65\u57f7\u884c\u7684(\u4e00\u6b65\u4e00\u6b65\u57f7\u884c\uff0c\u9019\u6b65\u9084\u6c92\u57f7\u884c\u5b8c\u7684\u8a71\u4e0d\u6703\u5230\u4e0b\u4e00\u6b65\u57f7\u884c)\u3002<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"2_%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C_JavaScript_%E7%9A%84%E7%BC%BA%E9%BB%9E\"><\/span>2. \u540c\u6b65\u57f7\u884c JavaScript \u7684\u7f3a\u9ede<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"21_%E9%98%BB%E5%A1%9E_block_%E5%BE%8C%E9%9D%A2%E7%A8%8B%E5%BC%8F%E7%A2%BC%E7%9A%84%E5%9F%B7%E8%A1%8C\"><\/span>2.1 \u963b\u585e (block) \u5f8c\u9762\u7a0b\u5f0f\u78bc\u7684\u57f7\u884c<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u56e0\u70ba JavaScript \u5f15\u64ce\u662f\u55ae\u57f7\u884c\u7dd2\uff0c\u6240\u4ee5\u540c\u6b65\u57f7\u884c\u4e00\u500b\u8017\u6642\u7684\u51fd\u6578\u6642\u5c31\u6703\u963b\u585e (block) \u5230\u5f8c\u9762\u7a0b\u5f0f\u7684\u57f7\u884c\u3002<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"22_%E5%9C%A8%E7%80%8F%E8%A6%BD%E5%99%A8%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E6%99%82%EF%BC%8C%E6%9C%83%E9%98%BB%E5%A1%9E%E7%95%AB%E9%9D%A2%E7%9A%84%E6%B8%B2%E6%9F%93render\"><\/span>2.2 \u5728\u700f\u89bd\u5668\u540c\u6b65\u57f7\u884c\u6642\uff0c\u6703\u963b\u585e\u756b\u9762\u7684\u6e32\u67d3(render)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7576 JavaScript \u5728\u700f\u89bd\u5668\u540c\u6b65\u57f7\u884c\u8017\u6642\u7684\u51fd\u6578\u6642\uff0c\u9664\u4e86\u6703\u963b\u585e (block) \u5f8c\u9762\u51fd\u6578\u7684\u57f7\u884c\u5916\uff0c\u9084\u6703\u963b\u585e\u6574\u500b\u7db2\u9801\u7684\u756b\u9762\uff0c\u8b93\u4f60\u6574\u500b\u7db2\u9801\u7684\u756b\u9762\u52d5\u5f48\u4e0d\u5f97\u3002\u70ba\u751a\u9ebc\u5462\uff1f\u6211\u5011\u5148\u4f86\u770b\u4e00\u4e0b\u700f\u89bd\u5668\u7684\u67b6\u69cb\uff1a<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-arch2.png\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-arch2.png\" alt=\"\" class=\"wp-image-1625\" width=\"649\" height=\"374\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-arch2.png 865w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-arch2-300x173.png 300w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-arch2-768x443.png 768w\" sizes=\"(max-width: 649px) 100vw, 649px\" \/><\/a><figcaption>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/developers.google.com\/web\/updates\/2018\/09\/inside-browser-part1\" target=\"_blank\" aria-label=\"Inside look at modern web browser (part 1) (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">Inside look at modern web browser (part 1)<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u700f\u89bd\u5668\u662f\u7531\u8a31\u591a\u4e0d\u540c\u7684 process \u6240\u7d44\u6210\uff0c\u4e0d\u540c\u7684 process \u8ca0\u8cac\u4e0d\u540c\u7684\u5de5\u4f5c\u5167\u5bb9\uff0c\u8209\u4f8b\u4f86\u8aaa\uff1a<\/p>\n\n\n\n<ul><li>Browser process: \u8ca0\u8cac\u700f\u89bd\u5668\u4e2d\u7684\u7db2\u5740\u5217\u3001\u4e0a\u4e00\u9801\u3001\u4e0b\u4e00\u9801\u6309\u9215\u3001\u66f8\u7c64\u3001\u7db2\u8def\u9023\u7dda\u3001\u6a94\u6848\u5b58\u53d6\u7b49\u7b49\u529f\u80fd\u3002<\/li><li>Plugin process: \u8ca0\u8cac\u700f\u89bd\u5668\u4e2d\u7684\u7b2c\u4e09\u65b9\u5957\u4ef6\uff0c\u50cf\u662f Adobe reader\u3001flash \u7b49\u7b49\u3002<\/li><li>GPU process: \u8ca0\u8cac\u5e6b\u52a9\u6e32\u67d3 (render) \u7db2\u9801\u4e2d\u7684\u5f71\u7247\u548c\u5716\u7247 \u3002<\/li><li>Renderer process: \u8ca0\u8cac\u6574\u500b\u7db2\u9801\u7684\u6e32\u67d3 (render) \uff0c\u57f7\u884c HTML\u3001CSS \u4ee5\u53ca JavaScript\u3002<\/li><\/ul>\n\n\n\n<p>\u6bcf\u500b process \u5404\u81ea\u8ca0\u8cac\u4e0d\u540c\u7684\u5de5\u4f5c\uff0c\u6bcf\u500b process \u53c8\u81f3\u5c11\u6709\u4e00\u500b thread (\u57f7\u884c\u7dd2) \u4f86\u8ca0\u8cac\u57f7\u884c\u76f8\u95dc\u5de5\u4f5c\u3002<br>\u5176\u4e2d HTML\u3001CSS \u7684\u89e3\u6790\u4ee5\u53ca JavaScript \u7684\u57f7\u884c\u662f\u7531 renderer process \u4e2d\u7684 main thread \u6240\u8ca0\u8cac\u7684\uff0c\u6240\u4ee5\u7576\u4f60\u7684 JavaScript \u57f7\u884c\u4e00\u500b\u5f88\u8017\u6642\u7684\u540c\u6b65\u5de5\u4f5c\u6642\uff0c\u5c31\u6703\u5c0e\u81f4\u7db2\u9801\u6c92\u8fa6\u6cd5\u6e32\u67d3 (render) \u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/renderer-process.png\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/renderer-process.png\" alt=\"Renderer process\" class=\"wp-image-1628\" width=\"649\" height=\"341\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/renderer-process.png 865w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/renderer-process-300x158.png 300w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/renderer-process-768x404.png 768w\" sizes=\"(max-width: 649px) 100vw, 649px\" \/><\/a><figcaption>Browser Renderer Process<br>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/developers.google.com\/web\/updates\/2018\/09\/inside-browser-part3\" target=\"_blank\" aria-label=\"Inside look at modern web browser (part 3) (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">Inside look at modern web browser (part 3)<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread.jpeg\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-1024x710.jpeg\" alt=\"browser main thread\" class=\"wp-image-1629\" width=\"768\" height=\"533\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-1024x710.jpeg 1024w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-300x208.jpeg 300w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-768x532.jpeg 768w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-1536x1065.jpeg 1536w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/browser-main-thread-2048x1420.jpeg 2048w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/><\/a><figcaption>Browser Main Thread in the Renderer Process<br>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/medium.com\/@francesco_rizzi\/javascript-main-thread-dissected-43c85fce7e23\" target=\"_blank\" aria-label=\"JavaScript main thread. Dissected. \ud83d\udd2c (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">JavaScript main thread. Dissected. \ud83d\udd2c<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u8209\u4f8b\u4f86\u8aaa\uff1a\u6211\u5beb\u4e86\u4e00\u500b\u53ef\u4ee5\u7528\u7db2\u9801\u8a08\u7b97\u51fa\u8cbb\u6c0f\u6578\u5217\u6700\u5f8c\u4e00\u500b\u6578\u5b57\u7684\u7a0b\u5f0f\uff0c\u7a0b\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"markup\" class=\"language-markup\">&lt;!DOCTYPE html>\n&lt;html>\n  &lt;head>\n    &lt;meta charset=\"UTF-8\" \/>\n    &lt;style>\n      .question {\n        width: 100%;\n        display: flex;\n        justify-content: center;\n        box-sizing: border-box;\n      }\n      .question:hover {\n        background-color: antiquewhite;\n      }\n    &lt;\/style>\n  &lt;\/head>\n  &lt;body>\n    &lt;h2 style=\"text-align: center;\">Compute Fibonacci !&lt;\/h2>\n    &lt;div\n      style=\"\n        margin-top: 15vh;\n        display: flex;\n        justify-content: center;\n        flex-wrap: wrap;\n      \"\n    >\n      &lt;div class=\"question\">\n        &lt;label for=\"\"\n          >Please enter variable.\n          &lt;input type=\"text\" id=\"variable\" \/>\n        &lt;\/label>\n        &lt;button id=\"start\">Start computing&lt;\/button>\n      &lt;\/div>\n      &lt;div style=\"margin-top: 10px\">\n        &lt;label for=\"\">\n          Answer:\n          &lt;input type=\"text\" id=\"answer\" \/>\n        &lt;\/label>\n      &lt;\/div>\n    &lt;\/div>\n  &lt;\/body>\n  &lt;script>\n    const fib = (num) => {\n      if (num &lt; 2) return num;\n      return fib(num - 1) + fib(num - 2);\n    };\n    const startComputing = () => {\n      const variable = document.getElementById(\"variable\").value;\n      const answer = fib(variable)\n      document.getElementById('answer').value = answer\n      console.log(\"Answer: \" + answer);\n    };\n    document.getElementById(\"start\").addEventListener(\"click\", startComputing);\n  &lt;\/script>\n&lt;\/html><\/code><\/pre>\n\n\n\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/\u5716\u7247-087.png\"><img loading=\"lazy\" width=\"694\" height=\"334\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/\u5716\u7247-087.png\" alt=\"\" class=\"wp-image-1634\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/\u5716\u7247-087.png 694w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/\u5716\u7247-087-300x144.png 300w\" sizes=\"(max-width: 694px) 100vw, 694px\" \/><\/a><\/figure><\/div>\n\n\n\n<p>\u7576\u9084\u6c92\u6309\u4e0b Start computing \u6309\u9215\u6642\uff0c\u628a\u6ed1\u9f20\u653e\u5230 Please enter variable \u4e0a\uff0c\u80cc\u666f\u984f\u8272\u6703\u6539\u8b8a(\u7c21\u55ae\u505a\u4e86\u4e00\u500b hover \u7684\u6548\u679c)\uff0c\u4f46\u7576\u6211\u8f38\u5165\u8b8a\u6578\uff0c\u4e26\u6309\u4e0b start computing \u5f8c\uff0c\u6703\u767c\u73fe\u7576\u700f\u89bd\u5668\u5728\u57f7\u884c\u9019\u500b\u51fd\u6578\u7684\u6642\u5019\uff0c\u6ed1\u9f20\u5c31\u7b97\u79fb\u5230 Please enter variable \u4e0a\u4e5f\u4e0d\u6703\u6709\u53cd\u61c9\uff0c\u6574\u500b\u7db2\u9801\u662f\u4e0d\u6703\u52d5\u7684\uff01(\u8f38\u516542 \u8a66\u770b\u770b)<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"23_%E8%A7%A3%E6%B1%BA%E7%80%8F%E8%A6%BD%E5%99%A8%E4%B8%AD%E9%98%BB%E5%A1%9E%E6%B8%B2%E6%9F%93%E7%9A%84%E5%95%8F%E9%A1%8C_%E2%80%93_Web_Worker\"><\/span>2.3 \u89e3\u6c7a\u700f\u89bd\u5668\u4e2d\u963b\u585e\u6e32\u67d3\u7684\u554f\u984c &#8211; Web Worker<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u700f\u89bd\u5668\u63d0\u4f9b\u4e86\u4e00\u500b API \uff0c\u8b93\u6211\u5011\u53ef\u4ee5\u89e3\u6c7a\u540c\u6b65\u57f7\u884c\u6642\u9047\u5230\u8017\u6642\u7684\u51fd\u6578\u5c0e\u81f4\u756b\u9762\u963b\u585e\u7684\u554f\u984c \u2014 Worker thread\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker.png\"><img loading=\"lazy\" width=\"550\" height=\"307\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker.png\" alt=\"web worker\" class=\"wp-image-1635\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker.png 550w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-300x167.png 300w\" sizes=\"(max-width: 550px) 100vw, 550px\" \/><\/a><figcaption>Web Worker<br>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/www.mdeditor.tw\/pl\/pyMe\/zh-hk\" target=\"_blank\" aria-label=\"\u4f60\u4e0d\u77e5\u9053\u7684 Web Workers \uff08\u4e0a\uff09 (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">\u4f60\u4e0d\u77e5\u9053\u7684 Web Workers \uff08\u4e0a\uff09<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u539f\u7406\u5c31\u662f\uff0c\u7576\u4f60\u9700\u8981\u57f7\u884c\u4e00\u500b\u5f88\u8017\u6642\u7684\u51fd\u6578\u6642\uff0c\u53ef\u4ee5\u7528 new Worker \u8a9e\u6cd5\u8acb\u700f\u89bd\u5668\u70ba\u4f60\u958b\u555f\u4e00\u500b worker thread \uff0c\u7528\u4f86\u57f7\u884c\u4f60\u8017\u6642\u7684 JavaScript \u51fd\u6578\uff0c\u8207\u6b64\u540c\u6642\uff0c\u4f60\u7684 JavaScript \u51fd\u6578\u4ecd\u6703\u7e7c\u7e8c\u540c\u6b65\u57f7\u884c\u4f60\u6240\u5beb\u7684\u7a0b\u5f0f\uff0c\u4e0d\u8b93\u8a72\u8017\u6642\u7a0b\u5f0f\u963b\u585e\u4f60\u5f8c\u9762\u7a0b\u5f0f\u7684\u57f7\u884c\u8207\u756b\u9762\u7684\u6e32\u67d3\u3002<br>\u4ee5\u525b\u525b\u7684\u4f8b\u5b50\u7528 Web worker \u6539\u5beb\uff0cJavaScript \u7684\u90e8\u5206\u5c31\u6703\u8b8a\u6210\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">const startComputing = () => {\n  \/\/ \u8acb\u700f\u89bd\u5668\u958b\u555f\u4e00\u500b\u65b0\u7684 worker thread\n  const worker = new Worker(\".\/fib.js\");\n  const variable = document.getElementById(\"variable\").value;\n  \/\/ \u628a\u4f7f\u7528\u8005\u8f38\u5165\u7684\u8b8a\u6578\u4e1f\u7d66 worker thread\n  worker.postMessage(variable);\n  \/\/ \u7528 worker.onmessage \u4f86\u76e3\u807d worker \u662f\u5426\u904b\u7b97\u5b8c\u7562\u4e26\u5c07\u7d50\u679c\u4e1f\u56de\u4f86\n  worker.onmessage = function(e) {\n    document.getElementById(\"answer\").value = e.data;\n    \/\/ \u904b\u7b97\u5b8c\u7562\u5f8c\u628a\u7d50\u679c\u5370\u51fa\u4f86\n    console.log(\"Answer: \" + e.data);\n    \/\/ \u5c07 worker thread \u7d66\u95dc\u6389\n    worker.terminate();\n  };\n  console.log('test');\n};\ndocument.getElementById(\"start\").addEventListener(\"click\", startComputing);<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">\/\/ fib.js\n\/\/ worker thread \u8981\u57f7\u884c\u7684\u6771\u897f\u5beb\u5728\u4e00\u500b\u65b0\u7684 js \u6a94\nconst fib = (num) => {\n  if (num &lt; 2) return num;\n  return fib(num - 1) + fib(num - 2);\n};\n\n\/\/ \u57f7\u884c\u5b8c\u7562\u5f8c\u4e1f\u56de main thread \u7e7c\u7e8c\u8655\u7406\nonmessage = function(e) {\n  postMessage(fib(e.data));\n}<\/code><\/pre>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1.png\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1-1024x609.png\" alt=\"web worker\" class=\"wp-image-1638\" width=\"768\" height=\"457\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1-1024x609.png 1024w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1-300x179.png 300w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1-768x457.png 768w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/web-worker-1.png 1489w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/><\/a><figcaption>Web Worker \u4f7f\u7528\u65b9\u6cd5\u53ca\u539f\u7406<br>\u5716\u7247\u4f86\u6e90\uff1a<a class=\"rank-math-link\" href=\"https:\/\/classroom.udacity.com\/courses\/ud860\/lessons\/4138168623\/concepts\/41840985580923\" target=\"_blank\" rel=\"noopener\">Bro<\/a><a href=\"https:\/\/classroom.udacity.com\/courses\/ud860\/lessons\/4138168623\/concepts\/41840985580923\" target=\"_blank\" aria-label=\"wser Rendering Optimization - JavaScript (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">wser Rendering Optimization &#8211; JavaScript<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u4ee5\u4e0a\u5c31\u662f\u5982\u4f55\u89e3\u6c7a\u540c\u6b65\u57f7\u884c\u5c0e\u81f4\u700f\u89bd\u5668\u756b\u9762\u963b\u585e\u7684\u65b9\u6cd5\uff0cWeb worker \u7684\u8a73\u7d30\u7528\u6cd5\u53ef\u4ee5\u53c3\u8003 <a href=\"https:\/\/developer.mozilla.org\/zh-TW\/docs\/Web\/API\/Web_Workers_API\/Using_web_workers\" target=\"_blank\" aria-label=\"\u4f7f\u7528Web Workers - Web APIs | MDN (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">\u4f7f\u7528Web Workers &#8211; Web APIs | MDN<\/a>\u3002<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"3_JavaScript_%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E5%8E%9F%E7%90%86_%E2%80%93_Call_Stack_%E7%9A%84%E8%A7%80%E5%BF%B5\"><\/span>3. JavaScript \u540c\u6b65\u57f7\u884c\u539f\u7406 &#8211; Call Stack \u7684\u89c0\u5ff5<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u7576 JavaScript \u5f15\u64ce\u5728\u57f7\u884c JavaScript \u6642\uff0c\u6703\u5c07\u76ee\u524d\u57f7\u884c\u5230\u54ea\u500b\u90e8\u5206\u8a18\u9304\u5728\u4e00\u500b\u53eb\u505a Call Stack \u7684\u8cc7\u6599\u7d50\u69cb\u4e2d\uff0c stack \u8cc7\u6599\u7d50\u69cb\u7684\u7279\u6027\u662f\u5f8c\u9032\u5148\u51fa (Last in First out,LIFO)\uff0c\u4ee5\u4e0b\u8aaa\u660e JavaScript \u57f7\u884c\u6642\u7684\u539f\u5247\uff1a<\/p>\n\n\n\n<ol><li>\u7576 JavaScript \u958b\u59cb\u57f7\u884c\u67d0\u51fd\u6578\u6642\uff0cinterpreter \u6703\u5c07\u8a72\u51fd\u6578\u653e\u9032 call stack \u7576\u4e2d<\/li><li>\u4efb\u4f55\u5728\u8a72\u51fd\u6578\u5167\u57f7\u884c\u7684\u51fd\u6578\uff0c\u6703\u88ab\u52a0\u9032call stack \u7684\u66f4\u4e0a\u9762<\/li><li>\u7576call stack \u4e2d\u6700\u4e0a\u9762\u7684\u51fd\u6578\u57f7\u884c\u5b8c\u7562 (\u51fd\u6578\u57f7\u884c\u5230\u6700\u5f8c\u4e00\u884c\u6216\u662f\u9047\u5230 return) \u5f8c\uff0c\u6703\u88ab pop \u6389\uff0c\u5f80\u4e0b\u57f7\u884c call stack \u4e2d\u7684\u51fd\u6578<\/li><\/ol>\n\n\n\n<p>\u8209\u500b\u7c21\u55ae\u7684\u4f8b\u5b50\u5c31\u53ef\u4ee5\u8aaa\u660e\u4e0a\u9762\u7684\u539f\u5247\u4e86\uff0c\u57f7\u884c\u4ee5\u4e0b JavaScript \uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">const bar = () => console.log('bar')\n\nconst baz = () => console.log('baz')\n\nconst foo = () => {\n  console.log('foo')\n  bar()\n  baz()\n}\n\nfoo()\n\n\/\/ foo\n\/\/ bar\n\/\/ baz<\/code><\/pre>\n\n\n\n<p>Call Stack \u7684\u9806\u5e8f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack.png\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack-980x1024.png\" alt=\"JavaScript Call Stack\" class=\"wp-image-1641\" width=\"735\" height=\"768\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack-980x1024.png 980w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack-287x300.png 287w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack-768x802.png 768w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-call-stack.png 1272w\" sizes=\"(max-width: 735px) 100vw, 735px\" \/><\/a><figcaption>\u5716\u7247\u4f86\u6e90\uff1a<a rel=\"noreferrer noopener\" href=\"https:\/\/flaviocopes.com\/node-event-loop\/\" target=\"_blank\">The Node.js Event Loop<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u4ee5\u4e0a\u5c31\u662f Call Stack \u7684\u89c0\u5ff5\u3002<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"4_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C\"><\/span>4. JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u9996\u5148\u5148\u4f86\u63a8\u85a6\u6700\u6dfa\u986f\u6613\u61c2\u8b1b\u89e3 JavaScript \u975e\u540c\u6b65\u539f\u7406\u7684\u5f71\u7247\uff1a<a rel=\"noreferrer noopener\" href=\"https:\/\/www.youtube.com\/watch?v=8aGhZQkoFbQ\" target=\"_blank\">What the heck is the event loop anyway? | Philip Roberts | JSConf EU<\/a>\uff0c\u975e\u5e38\u63a8\u85a6\u770b\u5b8c\u5f71\u7247\u5f8c\u518d\u4f86\u7e7c\u7e8c\u770b\u6587\u7ae0\uff0c\u6703\u6709\u6982\u5ff5\u5f88\u591a\u3002<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"41_%E7%82%BA%E7%94%9A%E9%BA%BC%E9%9C%80%E8%A6%81%E9%9D%9E%E5%90%8C%E6%AD%A5%EF%BC%9F\"><\/span>4.1 \u70ba\u751a\u9ebc\u9700\u8981\u975e\u540c\u6b65\uff1f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5728\u57f7\u884c JavaScript \u7684\u904e\u7a0b\u4e2d\uff0c\u6709\u6642\u5019\u6211\u5011\u4e26\u4e0d\u5e0c\u671b\u51fd\u6578\u88ab\u300c\u7acb\u523b\u300d\u57f7\u884c\uff0c\u800c\u662f\u9047\u5230\u67d0\u4e9b\u300c\u4e8b\u4ef6\u300d\u5f8c\u624d\u88ab\u57f7\u884c\uff0c\u4f8b\u5982\uff1a\u9ede\u64ca\u67d0\u500b\u6309\u9215\u5f8c\u624d\u53bb\u57f7\u884c\u67d0\u51fd\u6578\u3001\u7d93\u904e\u5e7e\u79d2\u5f8c\u518d\u57f7\u884c\u67d0\u500b\u51fd\u6578\u3001\u9001\u51fa http request \u5f8c\uff0c\u7b49\u63a5\u6536\u5230 response \u518d\u57f7\u884c\u67d0\u51fd\u6578\u7b49\u7b49\u3002\u56e0\u6b64\u6211\u5011\u9700\u8981 JavaScript \u9032\u884c\u975e\u540c\u6b65\u7684\u57f7\u884c\uff0c\u4ee5\u4e0b\u5716\u7247\u7c21\u55ae\u8aaa\u660e\u4e86\u540c\u6b65\u8207\u975e\u540c\u6b65\u7684\u6982\u5ff5\uff1a<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async.png\"><img loading=\"lazy\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async-1024x382.png\" alt=\"JavaScript Sync Async\" class=\"wp-image-1644\" width=\"768\" height=\"287\" srcset=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async-1024x382.png 1024w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async-300x112.png 300w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async-768x287.png 768w, https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/javascript-sync-async.png 1032w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/><\/a><figcaption>JavaScript Sync and Async<\/figcaption><\/figure><\/div>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"42_%E7%82%BA%E7%94%9A%E9%BA%BC%E7%80%8F%E8%A6%BD%E5%99%A8%E5%8F%AF%E4%BB%A5%E5%AF%A6%E7%8F%BE_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%EF%BC%9F\"><\/span>4.2 \u70ba\u751a\u9ebc\u700f\u89bd\u5668\u53ef\u4ee5\u5be6\u73fe JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\uff1f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u524d\u9762\u6709\u8aaa\u5230\u57f7\u884c JavaScript \u7684 JavaScript \u5f15\u64ce\u662f\u55ae\u57f7\u884c\u7dd2 (single thread)\uff0c\u4e00\u6b21\u53ea\u80fd\u505a\u4e00\u6b21\u4e8b\u60c5\uff0c\u7136\u800c\u700f\u89bd\u5668\u4e26\u4e0d\u662f\uff0c\u700f\u89bd\u5668\u4e2d\u6709\u8a31\u591a processes\uff0c\u6bcf\u500b process \u53c8\u81f3\u5c11\u6709\u4e00\u500b\u57f7\u884c\u7dd2 ( thread)\uff0c\u56e0\u6b64\u53ef\u4ee5\u5728\u700f\u89bd\u5668\u4e2d\u5be6\u8e10 JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\u3002<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"43_JavaScript_%E7%9A%84%E9%9D%9E%E5%90%8C%E6%AD%A5%E5%9F%B7%E8%A1%8C%E5%8E%9F%E7%90%86\"><\/span>4.3 JavaScript \u7684\u975e\u540c\u6b65\u57f7\u884c\u539f\u7406<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u700f\u89bd\u5668\u63d0\u4f9b\u4e86\u8a31\u591a\u975e\u540c\u6b65\u51fd\u6578\uff0c\u7576 JavaScript \u5f15\u64ce\u4e2d\u7684 Call Stack \u767c\u73fe\u57f7\u884c\u5230\u975e\u540c\u6b65\u51fd\u6578\u6642\uff0c\u6703\u5c07\u8a72\u975e\u540c\u6b65\u51fd\u6578\u7684\u89f8\u767c\u4e8b\u4ef6\u4ea4\u7d66\u700f\u89bd\u5668\u8655\u7406(\u53ef\u80fd\u662f\u5012\u6578\u8a08\u6642\u3001\u76e3\u807d\u4e8b\u4ef6\u7b49\u7b49)\uff0c\u7576\u8a72\u975e\u540c\u6b65\u51fd\u6578\u7684\u57f7\u884c\u689d\u4ef6\u88ab\u89f8\u767c\u6642(\u4f7f\u7528\u8005\u9ede\u64ca component \u6216\u662f\u5012\u6578\u6642\u9593\u5230)\u6642\uff0c\u518d\u5c07\u975e\u540c\u6b65\u51fd\u6578\u7684 callback function \u653e\u5230\u4e00\u500b\u53eb\u505a Callback Queue \u7684\u8cc7\u6599\u7d50\u69cb\u4e2d\u3002<br>\u700f\u89bd\u5668\u4e2d\u7684 event loop \u5247\u6703\u4e0d\u65b7\u76e3\u807d Call Stack \u4e2d\u662f\u5426\u6709\u9084\u6c92\u57f7\u884c\u5b8c\u7684\u51fd\u6578\uff0c\u4e00\u65e6 Call Stack \u4e2d\u70ba\u7a7a\uff0cevent loop \u5c31\u6703\u5c07 Callback Queue \u88e1\u7684\u7b2c\u4e00\u500b callback function \u653e\u5230 Call Stack \u4e2d\u57f7\u884c\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><a href=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-event-loop.gif\"><img loading=\"lazy\" width=\"800\" height=\"422\" src=\"https:\/\/jimmyswebnote.com\/wp-content\/uploads\/2021\/03\/JavaScript-event-loop.gif\" alt=\"JavaScript Event Loop\" class=\"wp-image-1647\"\/><\/a><figcaption>JavaScript Event Loop<br>\u5716\u7247\u4f86\u6e90\uff1a<a href=\"https:\/\/medium.com\/@Rahulx1\/understanding-event-loop-call-stack-event-job-queue-in-javascript-63dcd2c71ecd\" target=\"_blank\" aria-label=\"Understanding Event Loop, Call Stack, Event &amp; Job Queue in Javascript (opens in a new tab)\" rel=\"noreferrer noopener\" class=\"rank-math-link\">Understanding Event Loop, Call Stack, Event &amp; Job Queue in Javascript<\/a><\/figcaption><\/figure><\/div>\n\n\n\n<p>\u4ee5\u57f7\u884c <code>setTimeout(() =&gt; console.log('Success'), 2000)<\/code> \u9019\u500b\u51fd\u6578\u70ba\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<ol><li>Call Stack \u57f7\u884c\u5230 setTimout() \u9019\u500b\u51fd\u6578\uff0c\u767c\u73fe\u4ed6\u662f\u700f\u89bd\u5668\u63d0\u4f9b\u7684\u975e\u540c\u6b65\u51fd\u6578\uff0c\u56e0\u6b64\u4ea4\u7d66\u700f\u89bd\u5668\u958b\u59cb\u8a08\u6642\u3002<\/li><li>\u700f\u89bd\u5668\u958b\u59cb\u8a08\u6642 2 \u79d2\u9418\uff0c\u7576\u6642\u9593\u5230\u7684\u6642\u5019\uff0c\u5c07 setTimeout \u7684 Callback function (\u4e5f\u5c31\u662f <code>() =&gt; console.log('success)<\/code>)\u653e\u5230 Callback Queue \u4e2d\uff0c\u7b49\u5f85\u57f7\u884c\u3002<\/li><li>Event Loop \u4e0d\u65b7\u76e3\u807d Call Stack \u4e2d\u662f\u5426\u6709\u5c1a\u672a\u57f7\u884c\u5b8c\u7684\u51fd\u6578\uff0c\u4e00\u65e6\u767c\u73fe\u662f\u7a7a\u7684\uff0c\u5c31\u5c07 Callback Queue \u4e2d\u7684\u7b2c\u4e00\u500b\u51fd\u6578\u653e\u5230 Call Stack \u4e2d\u57f7\u884c\u3002<\/li><\/ol>\n\n\n\n<p>\u4ee5\u57f7\u884c <code>window.addEventListener('click', () =&gt; console.log('Click!'))<\/code>\u70ba\u4f8b\uff1a<\/p>\n\n\n\n<ol id=\"block-1461919c-ad84-4d3e-a477-12db20dcc7e4\"><li>Call Stack \u57f7\u884c\u5230 window.addEventListener() \u9019\u500b\u51fd\u6578\uff0c\u767c\u73fe\u4ed6\u662f\u700f\u89bd\u5668\u63d0\u4f9b\u7684\u975e\u540c\u6b65\u51fd\u6578\uff0c\u56e0\u6b64\u4ea4\u7d66\u700f\u89bd\u5668\u958b\u59cb\u76e3\u807d\u4e8b\u4ef6\u3002<\/li><li>\u700f\u89bd\u5668\u958b\u59cb\u76e3\u807d\u4e8b\u4ef6\uff0c\u7576\u4f7f\u7528\u8005\u9ede\u64ca\u8996\u7a97\u7684\u6642\u5019\uff0c\u5c07 window.addEventListener\u7684 Callback function (\u4e5f\u5c31\u662f <code>() =&gt; console.log('Click!')<\/code>)\u653e\u5230 Callback Queue \u4e2d\uff0c\u7b49\u5f85\u57f7\u884c\u3002<\/li><li>Event Loop \u4e0d\u65b7\u76e3\u807d Call Stack \u4e2d\u662f\u5426\u6709\u5c1a\u672a\u57f7\u884c\u5b8c\u7684\u51fd\u6578\uff0c\u4e00\u65e6\u767c\u73fe\u662f\u7a7a\u7684\uff0c\u5c31\u5c07 Callback Queue \u4e2d\u7684\u7b2c\u4e00\u500b\u51fd\u6578\u653e\u5230 Call Stack \u4e2d\u57f7\u884c\u3002<\/li><\/ol>\n\n\n\n<p>\u4ee5\u4e0a\u5c31\u662f\u700f\u89bd\u5668\u5982\u4f55\u5be6\u73fe JavaScript \u7684\u539f\u7406\uff0c\u5e0c\u671b\u5c0d\u4f60\u6709\u5e6b\u52a9\uff01<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"5_%E5%8F%83%E8%80%83%E8%B3%87%E6%96%99\"><\/span>5. \u53c3\u8003\u8cc7\u6599<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a aria-label=\"Inside look at modern web browser (opens in a new tab)\" href=\"https:\/\/developers.google.com\/web\/updates\/2018\/09\/inside-browser-part1\" target=\"_blank\" rel=\"noreferrer noopener\" class=\"rank-math-link\">Inside look at modern web browser<\/a><br><a aria-label=\"\u9032\u968e Javasctipt \u6982\u5ff5 (1) (opens in a new tab)\" href=\"https:\/\/medium.com\/@paulyang1234\/%E9%80%B2%E9%9A%8E-javasctipt-%E6%A6%82%E5%BF%B5-1-e1a175502db9\" target=\"_blank\" rel=\"noreferrer noopener\" class=\"rank-math-link\">\u9032\u968e Javasctipt \u6982\u5ff5 (1)<\/a><br><a aria-label=\"JavaScript main thread. Dissected. \ud83d\udd2c (opens in a new tab)\" href=\"https:\/\/medium.com\/@francesco_rizzi\/javascript-main-thread-dissected-43c85fce7e23\" target=\"_blank\" rel=\"noreferrer noopener\" class=\"rank-math-link\">JavaScript main thread. 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