\u603b\u51716\u9053\u9898\u3002\u4e0b\u9762\u662f\u7b54\u6848\uff0c\u505a\u5b8c\u518d\u770b\u770b\u3002<\/p>\n
1\u3002 [“1″,”2″,”3”].map(parseInt) \u4e3a\u591a\u5c11\uff1f<\/p>\n
2\u3002console.log(0.1+0.2 == 0.3)\u00a0\u00a0\u8f93\u51fa\u4ec0\u4e48\uff1f<\/p>\n
3\u3002var a = b =10;
\n(function(){
\nvar a = b = 20;
\n})();
\nconsole.log(a);
\nconsole.log(b);
\n\u95ee\uff1a\u8f93\u51fa\u7684 a = ?\u00a0 \u00a0 b = ?<\/p>\n
4\u3002
\nvar i = j =0;
\nfor(;i<5,j<10;i++,j++){
\nalert(‘helloword’)
\n}
\n\u95ee\uff1a\u8bf7\u95ee\u8f93\u51fa\u591a\u5c11\u4e2ahelloworld\uff1f<\/p>\n
5\u3002isNaN(123) = ?
\nisNaN(‘aaa’) = ?<\/p>\n
6.
\nvar name = ‘Tom’;
\nfunction\u00a0\u00a0a (){
\nvar name = ‘Peter’;
\nreturn
\n{
\nname : name
\n};
\n}<\/p>\n
\u95ee\uff1aa().name = ?<\/p>\n
\u4e0b\u9762\u662f\u7b54\u6848<\/span><\/p>\n ————————————-\u5206\u9694\u7ebf——————————————————-<\/p>\n \u7b54\u6848\uff1a \u4f60\u662f\u5426\u5168\u90e8\u7b54\u5bf9\u4e86\uff1f\u5168\u5bf9\u4e5f\u6ca1\u5956\u3002\u54c8\u54c8\u54c8\u3002\u4e0b\u9762\u89e3\u91ca\u4e00\u4e0b\u5427\u3002<\/p>\n \u7b2c\u4e00\u9898\uff1a \u7b2c\u4e8c\u9898\uff1a \u4e0b\u9762\u4e00\u5927\u4e32\u5c31\u662f\u590d\u5236\u522b\u4eba\u7684\u89e3\u91ca\u7684\u3002<\/p>\n js\u4e2d\u7684\u6570\u5b57\u90fd\u662f\u7528\u6d6e\u70b9\u6570\u8868\u793a\u7684\uff0c\u5e76\u89c4\u5b9a\u4f7f\u7528IEEE 754 \u6807\u51c6\u7684\u53cc\u7cbe\u5ea6\u6d6e\u70b9\u6570\u8868\u793a\u3002 \u6240\u4ee5\u51fa\u53bb\u505a\u7b14\u8bd5\u7684\u65f6\u5019\uff0c\u9898\u76ee\u5982\u679c\u8bf4\u8ba9\u4f60\u5199\u4e00\u4e2a\u6d6e\u70b9\u6570\u76f8\u52a0\u7684\u65b9\u6cd5\uff0c\u4f60\u5c31\u4e0d\u8981\u76f4\u63a5\u5199\u4e2areturn a+b \u4e86\u3002\u56e0\u4e3a\u4e0d\u4f1a\u6709\u4eba\u771f\u7684\u8003\u8fd9\u4e48\u7b80\u5355\u7684\u3002\u3002 \u7b2c\u4e09\u9898\uff1a \u7b2c\u56db\u9898\uff1a \u7b2c\u4e94\u9898\uff1a \u7b2c\u516d\u9898\uff1a \u597d\u7684\u3002\u76ee\u524d\u6211\u81ea\u5df1\u5c31\u9047\u5230\u8fc7\u8fd9\u4e48\u51e0\u4e2a\u6bd4\u8f83\u5751\u7684\u9898\uff0c\u540e\u7eed\u6709\u7684\u8bdd\u6211\u4f1a\u7ee7\u7eed\u52a0\u4e0a\u53bb\u7684\u3002<\/p>\n \u6b22\u8fce\u5206\u4eab\u672c\u6587\uff0c\u8f6c\u8f7d\u8bf7\u4fdd\u7559\u51fa\u5904\uff1a\u524d\u7aefABC<\/a> » \u51fa\u51e0\u4e2a\u9898\uff0c\u7b54\u5bf96\u4e2a\u7b97\u6211\u8f93<\/a><\/p>","protected":false},"excerpt":{"rendered":" \u603b\u51716\u9053\u9898\u3002\u4e0b\u9762\u662f\u7b54\u6848\uff0c\u505a\u5b8c\u518d\u770b\u770b\u3002 1\u3002 [“1″,”2″,”3”].map(parseInt) \u4e3a\u591a\u5c11\uff1f 2\u3002console […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/posts\/1697"}],"collection":[{"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1697"}],"version-history":[{"count":1,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/posts\/1697\/revisions"}],"predecessor-version":[{"id":1698,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=\/wp\/v2\/posts\/1697\/revisions\/1698"}],"wp:attachment":[{"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1697"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1697"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.qdabc.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1697"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n1.\u00a0\u00a0[“1”,NaN,NaN]2.\u00a0\u00a0false
\n3.\u00a0\u00a0a = 10\u00a0 \u00a0\u00a0\u00a0b = 20
\n4.\u00a0\u00a010\u4e2a
\n5.\u00a0\u00a0false\u00a0\u00a0true
\n6.\u00a0\u00a0undefined<\/p>\n
\n\u8fd9\u9898\u8981\u4e86\u89e3map\u65b9\u6cd5\u548cparseInt\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u3002
\nmap \u7684\u4e00\u822c\u4f7f\u7528\u662f\u00a0 \u00a0 arr.map(function(item,i){})
\nmap\u7684\u56de\u8c03\u65b9\u6cd5\u91cc\u9762\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u952e\u503c\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u662f\u952e\u540d\u3002
\n\u800cparseInt\u8fd9\u4e2a\u65b9\u6cd5\u4e5f\u662f\u6709\u4e24\u4e2a\u53c2\u6570\u7684\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u662f\u4ee3\u8868\u7684\u662f\u8fdb\u5236\u6570\u3002
\n\u5f53\u8fd9\u4e2a\u8fdb\u5236\u6570\u4e0d\u4f20\u6216\u8005\u4f200\u7684\u65f6\u5019\uff0c\u9ed8\u8ba4\u4e3a10\u8fdb\u5236\u3002
\n\u6240\u4ee5\u8fd9\u91cc\u9762\u904d\u5386\u7684\u65f6\u5019\uff0c\u4f20\u5165\u7684\u662f\u6570\u7ec4\u7684\u9ed8\u8ba4\u4e0b\u6807 0,1,2
\n\u6240\u4ee5\u904d\u5386\u7684\u7ed3\u679c\u662f\u6570\u7ec4\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u662f\u53ef\u4ee5\u6b63\u5e38\u663e\u793a\u3002\u4f20\u5165\u7684\u952e\u503c\u4e3a1\uff0c\u952e\u540d\u4e3a0\u00a0\u00a0\u8f93\u51fa1
\n\u800c\u7b2c\u4e8c\u6b21\u00a0\u00a0\u4f20\u5165\u952e\u503c\u4e3a2\uff0c\u952e\u540d\u4e3a1\u00a0\u00a0\u8f93\u51faNaN\u00a0\u00a0\u56e0\u4e3a1\u8fdb\u5236\u7684\u4e0d\u53ef\u80fd\u4f1a\u5927\u4e8e1\u7684\u3002
\n\u7b2c\u4e09\u6b21\u4f20\u5165\u952e\u503c\u4e3a3\uff0c\u952e\u540d\u4e3a2\u00a0\u00a0\u8f93\u51fa\u4e86NaN\u00a0\u00a0\u540c\u6837\u7684\uff0c\u4e8c\u8fdb\u5236\u662f\u4e0d\u4f1a\u51fa\u73b03\u7684\u3002<\/p>\n
\n\u8fd9\u9053\u9898\u4e3b\u8981\u8003\u4f60\u77e5\u4e0d\u77e5\u9053js\u7684\u6570\u5b57\u90fd\u662f\u6d6e\u70b9\u6570\u8868\u793a<\/p>\n
\nIEEE 754 \u89c4\u5b9a\u4e86\u4e24\u79cd\u57fa\u672c\u6d6e\u70b9\u683c\u5f0f\uff1a\u5355\u7cbe\u5ea6\u548c\u53cc\u7cbe\u5ea6\u3002
\nIEEE\u5355\u7cbe\u5ea6\u683c\u5f0f\u5177\u670924 \u4f4d\u6709\u6548\u6570\u5b57\u7cbe\u5ea6(\u5305\u542b\u7b26\u53f7\u53f7)\uff0c\u5e76\u603b\u5171\u5360\u752832 \u4f4d\u3002
\nIEEE\u53cc\u7cbe\u5ea6\u683c\u5f0f\u5177\u670953 \u4f4d\u6709\u6548\u6570\u5b57\u7cbe\u5ea6(\u5305\u542b\u7b26\u53f7\u53f7)\uff0c\u5e76\u603b\u5171\u5360\u752864 \u4f4d\u3002
\n\u5341\u8fdb\u52360.1\u00a0 \u00a0 => \u4e8c\u8fdb\u52360.00011001100110011\u2026(\u5faa\u73af0011)\u00a0 \u00a0\u00a0\u00a0=>\u5c3e\u6570\u4e3a1.1001100110011001100\u20261100\uff08\u517152\u4f4d\uff0c\u9664\u4e86\u5c0f\u6570\u70b9\u5de6\u8fb9\u76841\uff09\uff0c\u6307\u6570\u4e3a-4\uff08\u4e8c\u8fdb\u5236\u79fb\u7801\u4e3a00000000010\uff09,\u7b26\u53f7\u4f4d\u4e3a0\u00a0 \u00a0 => \u8ba1\u7b97\u673a\u5b58\u50a8\u4e3a\uff1a0 00000000100 10011001100110011\u202611001\u00a0 \u00a0 => \u56e0\u4e3a\u5c3e\u6570\u6700\u591a52\u4f4d\uff0c\u6240\u4ee5\u5b9e\u9645\u5b58\u50a8\u7684\u503c\u4e3a0.00011001100110011001100110011001100110011001100110011001
\n\u800c\u5341\u8fdb\u52360.2\u00a0 \u00a0 => \u4e8c\u8fdb\u52360.0011001100110011\u2026(\u5faa\u73af0011)\u00a0 \u00a0 =>\u5c3e\u6570\u4e3a1.1001100110011001100\u20261100\uff08\u517152\u4f4d\uff0c\u9664\u4e86\u5c0f\u6570\u70b9\u5de6\u8fb9\u76841\uff09\uff0c\u6307\u6570\u4e3a-3\uff08\u4e8c\u8fdb\u5236\u79fb\u7801\u4e3a00000000011\uff09,\u7b26\u53f7\u4f4d\u4e3a0\u00a0 \u00a0 => \u5b58\u50a8\u4e3a\uff1a0 00000000011 10011001100110011\u202611001\u00a0 \u00a0 \u56e0\u4e3a\u5c3e\u6570\u6700\u591a52\u4f4d\uff0c\u6240\u4ee5\u5b9e\u9645\u5b58\u50a8\u7684\u503c\u4e3a0.00110011001100110011001100110011001100110011001100110011
\n\u90a3\u4e48\u4e24\u8005\u76f8\u52a0\u5f97\uff1a\u00a0 \u00a0 0.00011001100110011001100110011001100110011001100110011001+\u00a0\u00a00.00110011001100110011001100110011001100110011001100110011\u00a0 \u00a0 =\u00a0\u00a00.01001100110011001100110011001100110011001100110011001100
\n\u8f6c\u6362\u621010\u8fdb\u5236\u4e4b\u540e\u5f97\u5230:0.30000000000000004<\/p>\n
\n\u89e3\u51b3\u65b9\u6cd5\u53ef\u4ee5\u4f7f\u7528\u5347\u5e42\u518d\u964d\u5e42\u3002\u4ee5\u8fd9\u9053\u9898\u4e3a\u4f8b\u7684\u8bdd\u3002\u5c31\u662f\u90fd\u5148\u4e58\u4ee510\uff0c\u76f8\u52a0\u540e\u518d\u9664\u4ee510.\u3002\u3002\u5982\u679c\u662f0.01+0.2\u90a3\u5c31\u90fd\u4e58\u4ee5100,\u4ee5\u6b64\u7c7b\u63a8\u3002<\/p>\n
\n\u8fd9\u9898\u8003\u7684\u5c31\u662f\u8fde\u7b49\u7684\u95ee\u9898\u3002\u6240\u4ee5\u8bf4\u8fde\u7b49\u4e0d\u8981\u968f\u4fbf\u4e71\u7528\u3002
\n\u8fde\u7b49\u8d4b\u503c\u7684\u65f6\u5019\uff0c\u5982a = b = c;
\n\u8fd9\u4e2a\u6267\u884c\u987a\u5e8f\u4ece\u53f3\u5f80\u5de6\u3002
\n\u5c31\u76f8\u5f53\u4e0eb = c;a = b;
\n\u5e76\u4e0d\u662f b=c; a = c;
\n\u6240\u4ee5\u56de\u5230\u9898\u76ee\u3002
\n\u4e00\u5f00\u59cb\u662fvar a = b = 10;
\n\u8fd9\u4e2a\u65f6\u5019\u5c31\u662fb = 10;var a = b; \u6240\u4ee5a = 10; \u56e0\u4e3ajs \u7684var\u58f0\u660e\u4e0d\u5728\u4e25\u683c\u6a21\u5f0f\u4e0b\u7684\u8bdd\uff0c\u662f\u53ef\u4ee5\u4e0d\u7528\u5199\u7684\uff0c\u56e0\u4e3ab \u4e0d\u5b58\u5728\uff0c\u6240\u4ee5\u4e5f\u81ea\u52a8\u58f0\u660e\u4e86\u3002
\n\u4e4b\u540e\u518d\u5728\u4e00\u4e2a\u7acb\u5373\u6267\u884c\u51fd\u6570\u91cc\u9762\uff0c\u5728\u8fd9\u4e2a\u4f5c\u7528\u57df\u4e0b\u6267\u884c\u4e86var a = b = 20;
\n\u5c31\u76f8\u5f53\u4e8eb = 20 ;var a = b; \u56e0\u4e3a\u8fd9\u65f6\u5019b\u5728\u5168\u5c40\u5916\u90e8\u5df2\u7ecf\u58f0\u660e\u4e86\u6240\u4ee5\u4fee\u6539\u7684\u5c31\u662f\u5168\u5c40\u7684\u53d8\u91cf\u3002
\n\u800ca\u524d\u9762\u8fd8\u6709var ,\u6240\u4ee5\u8fd9\u4e2aa\u53ea\u662f\u9488\u5bf9\u8be5\u4f5c\u7528\u57df\u4e0b\u7684\u53d8\u91cf\u3002\u5e76\u6ca1\u6709\u4fee\u6539\u5168\u5c40\u53d8\u91cf\u7684a.
\n\u6240\u4ee5\u5728\u5168\u5c40\u5916\u90e8\u6253\u5370a = 10\u00a0 \u00a0b = 20\u4e86\u3002<\/p>\n
\n\u8fd9\u9898\u5176\u5b9e\u8003\u5f97\u5c31\u662f\u9017\u53f7\u8fd0\u7b97\u7b26\u5566\u3002\u3002
\n\u5176\u5b9e\u4e2d\u95f4for\u5faa\u73af\u662f\u4e2a\u9017\u53f7\u8fd0\u7b97\u7b26\u3002
\ni<5,j<10 \u7684\u8ba1\u7b97\u7ed3\u679c\u5176\u5b9e\u5c31\u662fj<10\uff0c
\n\u6240\u4ee5\u6253\u537010\u4e2a\u3002<\/p>\n
\n\u8fd9\u9898\u5c31\u6ca1\u4ec0\u4e48\u597d\u8bf4\u7684\u3002
\n\u5c31\u662f\u8981\u77e5\u9053isNaN\u8fd9\u4e2a\u51fd\u6570\u7684\u610f\u4e49\u3002
\nisNaN() \u51fd\u6570\u7528\u4e8e\u68c0\u67e5\u5176\u53c2\u6570\u662f\u5426\u662f\u975e\u6570\u5b57\u503c\u3002
\n\u4e3a\u6570\u5b57\u65f6\u662ffalse,
\n\u4e0d\u4e3a\u6570\u5b57\u65f6\u662ftrue
\n\u6bd4\u8f83\u5bb9\u6613\u6df7\u6dc6\u3002<\/p>\n
\n\u8fd9\u9898\u5c31\u8003\u7ec6\u5fc3\u4e86\u3002\u3002
\n\u4e3a\u4ec0\u4e48\u662fundefined?
\n\u56e0\u4e3a\u4f60\u5728return\u90a3\u91cc\u6362\u884c\u4e86\u554a\u3002\u3002
\njs\u672b\u5c3e\u7684 ; \u7ecf\u5e38\u662f\u53ef\u4ee5\u7701\u7565\u7684\u3002\u6240\u4ee5\u4f60\u8fd9\u91cc\u8fdb\u884c\u6362\u884c\u4e86\u3002\u5c31\u76f8\u5f53\u4e8ereturn;
\n\u90a3\u540e\u9762\u7684\u4e1c\u897f\u80af\u5b9a\u4e5f\u4e0d\u4f1a\u6267\u884c\u4e86\u3002
\n\u6240\u4ee5\u4e0d\u8981\u4e71\u6362\u884c\u3002<\/p>\n