{"id":3619,"date":"2018-12-26T19:26:02","date_gmt":"2018-12-26T11:26:02","guid":{"rendered":"http:\/\/gaigaiming.com\/?p=3619"},"modified":"2018-12-26T19:26:02","modified_gmt":"2018-12-26T11:26:02","slug":"js%e5%87%bd%e6%95%b0%e5%b8%a6%e6%8b%ac%e5%8f%b7%e5%92%8c%e4%b8%8d%e5%b8%a6%e6%8b%ac%e5%8f%b7%e7%9a%84%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"https:\/\/www.gaigaiming.com\/index.php\/2018\/12\/26\/js%e5%87%bd%e6%95%b0%e5%b8%a6%e6%8b%ac%e5%8f%b7%e5%92%8c%e4%b8%8d%e5%b8%a6%e6%8b%ac%e5%8f%b7%e7%9a%84%e5%8c%ba%e5%88%ab\/","title":{"rendered":"js\u51fd\u6570\u5e26\u62ec\u53f7\u548c\u4e0d\u5e26\u62ec\u53f7\u7684\u533a\u522b"},"content":{"rendered":"\n<p>\u5148\u8bf4\u7ed3\u679c<\/p>\n\n\n\n<p>1\u3001\u52a0\u4e86\u62ec\u53f7\u7684\u4ee3\u8868\u6267\u884c\u5b8c\u6bd5\u5f97\u5230\u51fd\u6570\u7684\u7ed3\u679c\uff08\u62ec\u53f7\u7684\u4e8c\u4e49\u6027\uff0c\u662f\u201c\u51fd\u6570\u7684\u8c03\u7528\u8fd0\u7b97\u7b26\u201d\uff09<\/p>\n\n\n\n<p>2\u3001\u6ca1\u52a0\u62ec\u53f7\u7684\uff0c\u67e5\u770b\u8be5\u51fd\u6570\u7684\u5b8c\u6574\u4fe1\u606f\u3002\u6307\u5411\u51fd\u6570\u7684\u6307\u9488\uff0c\u53ea\u662f\u4f20\u9012\u4e86\u51fd\u6570\u9898\u6240\u5728\u7684\u5730\u5740\u4f4d\u7f6e\u3002<\/p>\n\n\n\n<p>\u4e3e\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/demo1\nfunction demo1() {\n    var m = 3;\n    alert(m);\n}\nfunction demo2() {\n    var m = 55;\n    alert(m);\n}\n\nvar e = document.getElementById('btn'); \n   \n\/\/ \u70b9\u51fb\u7684\u65f6\u5019\u624d\u8fdb\u884c\u6267\u884c  \u70b9\u51fb\u6309\u94ae\u201cbtn\u201d\u540e\u5f39\u51fa3\ne.addEventListener('click', demo1); \n    \n\/\/ \u76f4\u63a5\u5c31\u5df2\u7ecf\u5f39\u51fa\u8fdb\u884c\u4e86\u6267\u884c \u5f39\u51fa55    \ne.addEventListener('click', demo2());\n\n\/\/demo2\nfunction foo(){\n var m = 3;\nreturn m;\n}\nvar a = foo;\nvar b = foo();\nconsole.log(a); \/\/\u51fd\u6570\u4f53\nconsole.log(b);\/\/3<\/code><\/pre>\n\n\n\n<p><\/p>\n\n\n\n<p>\u5176\u4e2d\u62ec\u53f7\u7684\u4e8c\u4e49\u6027\u3002\u611f\u89c9\u50cf\u901a\u5047\u5b57\uff0c\u53ef\u4ee5\u6709\u4fe9\u610f\u601d\u3002\u6bd4\u5982\u4e00\u4e2a\u7528\u7ea2\u8272\u58a8\u6c34\u5199\u7684\u201c\u84dd\u201d\u5b57\u3002\u8fd9\u4e2a\u5b57\u662f\u4ec0\u4e48\u989c\u8272\uff1f\u84dd\uff1f\u7ea2\uff1f<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>2.7.2 \u62ec\u53f7\"( )\"\u7684\u4e8c\u4e49\u6027\n\n\u6211\u4eec\u6765\u770b\u4e0b\u9762\u8bed\u53e5\u4e2d\u7684\u62ec\u53f7\"( )\"\u5e94\u8be5\u662f\u4ec0\u4e48\u542b\u4e49\u5462\uff1f\n\nvar str = typeof(123);  \nvar str = ('please input a string', 1000); \n\u7b2c\u4e00\u4e2a typeof \u770b\u8d77\u6765\u597d\u50cf\u88ab\u5f53\u6210\u4e86\u51fd\u6570\u4f7f\u7528--\u8fd9\u662f\u5426\u8bf4\u660e typeof \u4e3a\u4e00\u4e2a\"\u5185\u90e8\u51fd\u6570\"\u5462\uff1f\u800c\u7b2c\u4e8c\u884c\u4ee3\u7801\uff0c\u4f60\u76f8\u4fe1\u5b83\u4f1a\u6210\u529f\u6267\u884c\u5e76\u4f7f str\"\u610f\u5916\u5730\"\u8d4b\u503c\u4e3a 1000 \u5417\uff1f\u62ec\u53f7\u9996\u5148\u53ef\u4ee5\u4f5c\u4e3a\u8bed\u53e5\u4e2d\u7684\u8bcd\u6cd5\u5143\u7d20\u3002\u4f8b\u5982\u51fd\u6570\u58f0\u660e\u4e2d\u7684\"\u865a\u62df\u53c2\u6570\u8868\"\uff1a\n\/\/\u58f0\u660e\u51fd\u6570\u65f6\uff0c\u62ec\u53f7\u7528\u505a\u53c2\u6570\u8868  \nfunction foo(v1, v2) {  \n\/\/\u2026  \n} \n\u7b2c\u4e8c\u79cd\u60c5\u51b5\uff0c\u5c31\u662f\u62ec\u53f7\u53ea\u4f5c\u4e3a\"\u4f20\u503c\u53c2\u6570\u8868\uff08\u8fd9\u6709\u522b\u4e8e\u51fd\u6570\u58f0\u660e\u4e2d\u7684'\u865a\u62df\u53c2\u6570\u8868'\uff09\"\uff0c\u6ce8\u610f\u8fd9\u91cc\u5b83\u5e76\u4e0d\u8868\u8fbe\u51fd\u6570\u8c03\u7528\u7684\u542b\u4e49\u3002\u76ee\u524d\u4e3a\u6b62\uff0c\u5b83\u53ea\u51fa\u73b0\u5728 new \u5173\u952e\u5b57\u7684\u4f7f\u7528\u4e2d\uff1anew\u5173\u952e\u5b57\u7528\u4e8e\u521b\u5efa\u4e00\u4e2a\u5bf9\u8c61\u5b9e\u4f8b\u5e76\u8d1f\u8d23\u8c03\u7528\u8be5\u6784\u9020\u5668\u51fd\u6570\uff0c\u5982\u679c\u5b58\u5728\u4e00\u5bf9\u62ec\u53f7\"( )\"\u6307\u793a\u7684\u53c2\u6570\u8868\uff0c\u5219\u5728\u8c03\u7528\u6784\u9020\u5668\u51fd\u6570\u65f6\u4f20\u5165\u8be5\u53c2\u6570\u8868\uff0c\u5bf9\u6b64\u7684\u5177\u4f53\u5206\u6790\uff0c\u6211\u4eec\u5df2\u7ecf\u5728\"2.5.1.1\u4f7f\u7528\u6784\u9020\u5668\u521b\u5efa\u5bf9\u8c61\u5b9e\u4f8b\"\u4e2d\u8bb2\u8ff0\u8fc7\u4e86\u3002\u4f8b\u5982\uff1a\n\/\/\u6784\u9020\u5bf9\u8c61\u65f6\uff0c\u7528\u4e8e\u4f20\u5165\u521d\u59cb\u5316\u53c2\u6570  \nvar myArray = new Array('abc', 1, true); \n\u63a5\u4e0b\u6765\uff0c\u5b83\u4e5f\u53ef\u4ee5\u5728 with\u3001for\u3001if\u3001while \u548c do...while \u7b49\u8bed\u53e5\uff0c\u4ee5\u53ca catch()\u7b49\u5b50\u53e5\u4e2d\u7528\u6765\u4f5c\u4e3a\u9650\u5b9a\u8868\u8fbe\u5f0f\u7684\u8bcd\u6cd5\u5143\u7d20\uff1a\n\/\/ for\u8bed\u53e5(for\u2026in\u8bed\u53e5\u7c7b\u540c)  \nfor ( initialize; test; increment )  \nstatement  \n \n\/\/ if\u8bed\u53e5  \nif ( expression )  \nstatement  \n \n\/\/ while\u8bed\u53e5  \nwhile ( expression )  \nstatement  \n \n\/\/ do\u2026while\u8bed\u53e5  \ndo  \nstatement  \nwhile ( expression ) \n\u5728\u5145\u5f53 if\u3001while \u548c do...while \u8bed\u53e5\u4e2d\u7684\u8bcd\u6cd5\u5143\u7d20\u65f6\uff0c\u62ec\u53f7\u4f1a\u6709\"\u5c06\u8868\u8fbe\u5f0f\u7ed3\u679c\u8f6c\u6362\u4e3a\u5e03\u5c14\u503c\"\u7684\u526f\u4f5c\u7528\uff08\u53c2\u89c1\"5.7.3.2\u8bed\u53e5\uff08\u8bed\u4e49\uff09\u5bfc\u81f4\u7684\u7c7b\u578b\u8f6c\u6362\"\uff09\u3002\u5728\u5f88\u591a\u65f6\u5019\uff0c\u8bed\u53e5\u4e2d\u7684\u62ec\u53f7\u4f1a\u4ea7\u751f\u7c7b\u4f3c\u4e8e\"\u8fd0\u7b97\"\u8fd9\u6837\u7684\u9644\u52a0\u6548\u679c\u3002\n\n\u7b2c\u56db\u79cd\u60c5\u51b5\uff0c\u662f\u62ec\u53f7\"( )\"\u7528\u4e8e\u5f3a\u5236\u8868\u8fbe\u5f0f\u8fd0\u7b97\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u57fa\u672c\u542b\u4e49\u662f\u6211\u4eec\u901a\u5e38\u8bf4\u7684\u5f3a\u5236\u8fd0\u7b97\u4f18\u5148\u7ea7\u3002\u4f46\u4e8b\u5b9e\u4e0a\uff0c\u4e0d\u7ba1\u6709\u6ca1\u6709\u4f18\u5148\u7ea7\u7684\u95ee\u9898\uff0c\u62ec\u53f7\u603b\u662f\u4f1a\u5f3a\u5236\u5176\u5185\u90e8\u7684\u4ee3\u7801\u4f5c\u4e3a\u8868\u8fbe\u5f0f\u8fd0\u7b97\u3002\u4f8b\u5982\u6211\u4eec\u5728\u8fd9\u4e00\u5c0f\u8282\u5f00\u59cb\u5217\u4e3e\u7684\u4f8b\u5b50\uff1a\n\nvar str1 = typeof(123);  \nvar str2 = ('please input a string', 1000); \n\u5728\u7b2c 1 \u884c\u4ee3\u7801\u4e2d\uff0c\"( )\"\u5f3a\u5236 123 \u4f5c\u4e3a\u5355\u503c\u8868\u8fbe\u5f0f\u8fd0\u7b97\uff0c\u5f53\u7136\u8fd0\u7b97\u7ed3\u679c\u8fd8\u662f 123\uff0c\u4e8e\u662f\u518d\u8fdb\u884c typeof \u8fd0\u7b97\u3002\u6240\u4ee5\u8fd9\u91cc\u7684\u4e00\u5bf9\u62ec\u53f7\u8d77\u5230\u4e86\u5f3a\u5236\u8fd0\u7b97\u7684\u4f5c\u7528\u3002\u540c\u6837\u7684\u9053\u7406\uff0c\u7b2c 2 \u884c\u4ee3\u7801\u91cc\u7684\u4e00\u5bf9\u62ec\u53f7\u4e5f\u8d77\u5230\u76f8\u540c\u7684\u4f5c\u7528\uff0c\u5b83\u5f3a\u5236\u4e24\u4e2a\u5355\u503c\u8868\u8fbe\u5f0f\u505a\u8fde\u7eed\u8fd0\u7b97\uff0c\u7531\u4e8e\u8fde\u7eed\u8fd0\u7b97\u7b26\",\"\u7684\u8fd4\u56de\u503c\u662f\u6700\u540e\u4e00\u4e2a\u8868\u8fbe\u5f0f\u7684\u503c\uff0c\u56e0\u6b64\u8fd9\u4e2a\u7ed3\u679c\u8fd4\u56de\u4e86 1000\u3002\u6240\u4ee5\u6211\u4eec\u8981\u610f\u8bc6\u5230\uff0c\u4e0a\u9762\u7684\u7b2c 1 \u884c\u4ee3\u7801\u5e76\u6ca1\u6709\u8c03\u7528\u51fd\u6570\u7684\u610f\u601d\uff0c\u800c\u7b2c 2 \u884c\u4ee3\u7801\u5c06\u4f7f str2 \u88ab\u8d4b\u503c\u4e3a 1000\u3002\n\n\u6700\u540e\u4e00\u79cd\u60c5\u51b5\u6700\u4e3a\u5e38\u89c1\uff1a\u4f5c\u4e3a\u51fd\u6570\/\u65b9\u6cd5\u8c03\u7528\u8fd0\u7b97\u7b26\u3002\u4f8b\u5982\uff1a\n\n\/\/\u6709()\uff0c\u8868\u660e\u51fd\u6570\u8c03\u7528  \nfoo();  \n\/\/\u6ca1\u6709()\uff0c\u5219\u8be5\u8bed\u53e5\u53ea\u662f\u4e00\u4e2a\u53d8\u91cf\u7684\u8fd4\u56de\u3002  \nfoo; \n\u6211\u4eec\u4e00\u518d\u5f3a\u8c03\uff1a\u51fd\u6570\u8c03\u7528\u8fc7\u7a0b\u4e2d\u7684\u62ec\u53f7\"( )\"\u662f\u8fd0\u7b97\u7b26\u3002\u4e5f\u56e0\u6b64\u5f97\u51fa\u63a8\u8bba\uff0c\u5f53\"( )\"\u4f5c\u4e3a\u8fd0\u7b97\u7b26\u65f6\uff0c\u5b83\u53ea\u4f5c\u7528\u4e8e\u8868\u8fbe\u5f0f\u8fd0\u7b97\uff0c\u800c\u4e0d\u53ef\u80fd\u4f5c\u7528\u4e8e\u8bed\u53e5\u3002\u6240\u4ee5\u4f60\u53ea\u80fd\u5c06\u4f4d\u4e8e\uff1a\nfunction foo() {  \nreturn( 1 + 2);  \n} \n\u8fd9\u4e2a\u51fd\u6570\u5185\u7684\u3001return \u4e4b\u540e\u7684\u62ec\u53f7\u7406\u89e3\u6210\"\u5f3a\u5236\u8868\u8fbe\u5f0f\u4f18\u5148\u7ea7\"\uff0c\u800c\u4e0d\u662f\u7406\u89e3\u6210\"\u628a return\u5f53\u6210\u51fd\u6570\u6216\u8fd0\u7b97\u7b26\u4f7f\u7528\"\u3002\u6240\u4ee5\u4ece\u4ee3\u7801\u683c\u5f0f\u5316\u7684\u89d2\u5ea6\u4e0a\u6765\u8bf4\uff0c\u5728\u4e0b\u9762\u4e24\u79cd\u4e66\u5199\u65b9\u6cd5\u4e2d\uff0c\u7b2c\u4e8c\u79cd\u624d\u662f\u6b63\u786e\u7684\uff1a\n\n\/\/\u7b2c\u4e00\u79cd\uff0c\u50cf\u51fd\u6570\u8c03\u7528\u4e00\u6837\uff0creturn\u540e\u65e0\u7a7a\u683c  \nreturn(1 + 2);  \n \n\/\/\u7b2c\u4e8c\u79cd\uff0creturn\u540e\u7f6e\u4e00\u7a7a\u683c  \nreturn (1 + 2); \n\u57fa\u4e8e\u540c\u6837\u7684\u7406\u7531\uff0c\u65e0\u8bba\"break (my_label)\"\u770b\u8d77\u6765\u5982\u4f55\u5408\u7406\uff0c\u4e5f\u4f1a\u88ab\u5f15\u64ce\u8bc6\u522b\u4e3a\u8bed\u6cd5\u9519\u8bef\u3002\u56e0\u4e3a my_label \u53ea\u662f\u4e00\u4e2a\u6807\u7b7e\uff0c\u800c\u4e0d\u662f\u53ef\u4ee5\u4ea4\u7ed9\"( )\"\u8fd0\u7b97\u7b26\u5904\u7406\u7684\u8fd0\u7b97\u5143\uff0c\u6807\u7b7e\u4e0e\u8fd0\u7b97\u5143\u5c5e\u4e8e\u4e24\u4e2a\u5404\u81ea\u72ec\u7acb\u7684\u3001\u53ef\u91cd\u590d\uff08\u800c\u4e0d\u53d1\u751f\u8986\u76d6\uff09\u7684\u6807\u8bc6\u7b26\u7cfb\u7edf\u3002<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u5148\u8bf4\u7ed3\u679c 1\u3001\u52a0\u4e86\u62ec\u53f7\u7684\u4ee3\u8868\u6267\u884c\u5b8c\u6bd5\u5f97\u5230\u51fd\u6570\u7684\u7ed3\u679c\uff08\u62ec\u53f7\u7684\u4e8c\u4e49\u6027\uff0c\u662f\u201c\u51fd\u6570\u7684\u8c03\u7528\u8fd0\u7b97\u7b26\u201d\uff09 2\u3001\u6ca1\u52a0\u62ec\u53f7\u7684\uff0c\u67e5 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-3619","post","type-post","status-publish","format-standard","hentry","category-4"],"_links":{"self":[{"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/posts\/3619","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/comments?post=3619"}],"version-history":[{"count":0,"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/posts\/3619\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/media?parent=3619"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/categories?post=3619"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gaigaiming.com\/index.php\/wp-json\/wp\/v2\/tags?post=3619"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}