{"id":1779,"date":"2010-07-30T20:45:22","date_gmt":"2010-07-30T12:45:22","guid":{"rendered":"\/?p=1779"},"modified":"2020-01-16T23:53:57","modified_gmt":"2020-01-16T15:53:57","slug":"1779","status":"publish","type":"post","link":"https:\/\/www.justzz.com\/spec\/1779.html","title":{"rendered":"JavaScript\u57fa\u672c\u5bf9\u8c61"},"content":{"rendered":"
\n

Number \u201c\u6570\u5b57\u201d\u5bf9\u8c61<\/strong><\/span><\/p>\n

 <\/p>\n

\u5c5e\u6027<\/strong><\/span><\/p>\n

 <\/p>\n

 <\/p>\n

MAX_VALUE<\/strong> \u7528\u6cd5\uff1aNumber.MAX_VALUE\uff1b\u8fd4\u56de\u201c\u6700\u5927\u503c\u201d\u3002
\nMIN_VALUE<\/strong> \u7528\u6cd5\uff1aNumber.MIN_VALUE\uff1b\u8fd4\u56de\u201c\u6700\u5c0f\u503c\u201d\u3002
\nNaN<\/strong> \u7528\u6cd5\uff1aNumber.NaN \u6216 NaN\uff1b\u8fd4\u56de\u201cNaN\u201d\u3002\u201cNaN\u201d\uff08\u4e0d\u662f\u6570\u503c\uff09\u3002
\nNEGATIVE_INFINITY<\/strong> \u7528\u6cd5\uff1aNumber.NEGATIVE_INFINITY\uff1b\u8fd4\u56de\uff1a\u8d1f\u65e0\u7a77\u5927\uff0c\u6bd4\u201c\u6700\u5c0f\u503c\u201d\u8fd8\u5c0f\u7684\u503c\u3002
\nPOSITIVE_INFINITY<\/strong> \u7528\u6cd5\uff1aNumber.POSITIVE_INFINITY\uff1b\u8fd4\u56de\uff1a\u6b63\u65e0\u7a77\u5927\uff0c\u6bd4\u201c\u6700\u5927\u503c\u201d\u8fd8\u5927\u7684\u503c\u3002<\/p>\n

 <\/p>\n

\u65b9\u6cd5<\/strong><\/span><\/p>\n

 <\/p>\n

toString() \u7528\u6cd5<\/strong>\uff1a<\u6570\u503c\u53d8\u91cf>.toString()\uff1b\u8fd4\u56de\uff1a\u5b57\u7b26\u4e32\u5f62\u5f0f\u7684\u6570\u503c\u3002
\n\u5982\uff1a a == 123;alert(a.toString() == '123');\u3002<\/span><\/p>\n

 <\/p>\n

String \u5b57\u7b26\u4e32\u5bf9\u8c61<\/strong><\/span><\/p>\n

 <\/p>\n

\u5c5e\u6027<\/strong><\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 length<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.length\uff1b\u8fd4\u56de\u8be5\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\u3002<\/span><\/p>\n

 <\/p>\n

\u65b9\u6cd5<\/strong><\/span><\/p>\n

 <\/p>\n

charAt()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.charAt(<\u4f4d\u7f6e>)\uff1b\u8fd4\u56de\u8be5\u5b57\u7b26\u4e32\u4f4d\u4e8e\u7b2c<\u4f4d\u7f6e>\u4f4d\u7684\u5355\u4e2a\u5b57\u7b26\u3002
\n\u6ce8\u610f\uff1a\u5b57\u7b26\u4e32\u4e2d\u7684\u4e00\u4e2a\u5b57\u7b26\u662f\u7b2c 0 \u4f4d\u7684\uff0c\u7b2c\u4e8c\u4e2a\u624d\u662f\u7b2c 1 \u4f4d\u7684\uff0c\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u662f\u7b2c length- 1 \u4f4d\u7684\u3002<\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 charCodeAt()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.charCodeAt(<\u4f4d\u7f6e>)\uff1b\u8fd4\u56de\u8be5\u5b57\u7b26\u4e32\u4f4d\u4e8e\u7b2c<\u4f4d\u7f6e>\u4f4d\u7684\u5355\u4e2a\u5b57\u7b26\u7684 ASCII \u7801\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 fromCharCode()<\/strong> \u7528\u6cd5\uff1aString.fromCharCode(a, b, c...)\uff1b\u8fd4\u56de\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u8be5\u5b57\u7b26\u4e32\u6bcf\u4e2a\u5b57\u7b26\u7684 ASCII \u7801\u7531 a, b, c... \u7b49\u6765\u786e\u5b9a\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 indexOf()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.indexOf(<\u53e6\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61>[, <\u8d77\u59cb\u4f4d\u7f6e>])\uff1b\u8be5\u65b9\u6cd5\u4ece<\u5b57\u7b26\u4e32\u5bf9\u8c61>\u4e2d\u67e5\u627e<\u53e6\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61>\uff08\u5982\u679c\u7ed9\u51fa<\u8d77\u59cb\u4f4d\u7f6e>\u5c31\u5ffd\u7565\u4e4b\u524d\u7684\u4f4d\u7f6e\uff09\uff0c\u5982\u679c\u627e\u5230\u4e86\uff0c\u5c31\u8fd4\u56de\u5b83\u7684\u4f4d\u7f6e\uff0c\u6ca1\u6709\u627e\u5230\u5c31\u8fd4\u56de\u201c-1\u201d\u3002\u6240\u6709\u7684\u201c\u4f4d\u7f6e\u201d\u90fd\u662f\u4ece\u96f6\u5f00\u59cb\u7684\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 lastIndexOf()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.lastIndexOf(<\u53e6\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61>[, <\u8d77\u59cb\u4f4d\u7f6e>])\uff1b\u8ddf indexOf() \u76f8\u4f3c\uff0c\u4e0d\u8fc7\u662f\u4ece\u540e\u8fb9\u5f00\u59cb\u627e\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 split()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.split(<\u5206\u9694\u7b26\u5b57\u7b26>)\uff1b\u8fd4\u56de\u4e00\u4e2a\u6570\u7ec4\uff0c\u8be5\u6570\u7ec4\u662f\u4ece<\u5b57\u7b26\u4e32\u5bf9\u8c61>\u4e2d\u5206\u79bb\u5f00\u6765\u7684\uff0c<\u5206\u9694\u7b26\u5b57\u7b26>\u51b3\u5b9a\u4e86\u5206\u79bb\u7684\u5730\u65b9\uff0c\u5b83\u672c\u8eab\u4e0d\u4f1a\u5305\u542b\u5728\u6240\u8fd4\u56de\u7684\u6570\u7ec4\u4e2d\u3002
\n\u4f8b\uff1a<\/span>'1&2&345&678'.split('&')<\/span>\u8fd4\u56de\u6570\u7ec4\uff1a1,2,345,678<\/span>\u3002<\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 substring()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.substring(<\u59cb>[, <\u7ec8>])\uff1b\u8fd4\u56de\u539f\u5b57\u7b26\u4e32\u7684\u5b50\u5b57\u7b26\u4e32\uff0c\u8be5\u5b57\u7b26\u4e32\u662f\u539f\u5b57\u7b26\u4e32\u4ece<\u59cb>\u4f4d\u7f6e\u5230<\u7ec8>\u4f4d\u7f6e\u7684\u524d\u4e00\u4f4d\u7f6e\u7684\u4e00\u6bb5\u3002<\u7ec8> - <\u59cb> = \u8fd4\u56de\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff08length\uff09\u3002\u5982\u679c\u6ca1\u6709\u6307\u5b9a<\u7ec8>\u6216\u6307\u5b9a\u5f97\u8d85\u8fc7\u5b57\u7b26\u4e32\u957f\u5ea6\uff0c\u5219\u5b50\u5b57\u7b26\u4e32\u4ece<\u59cb>\u4f4d\u7f6e\u4e00\u76f4\u53d6\u5230\u539f\u5b57\u7b26\u4e32\u5c3e\u3002\u5982\u679c\u6240\u6307\u5b9a\u7684\u4f4d\u7f6e\u4e0d\u80fd\u8fd4\u56de\u5b57\u7b26\u4e32\uff0c\u5219\u8fd4\u56de\u7a7a\u5b57\u7b26\u4e32\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 substr()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.substr(<\u59cb>[, <\u957f>])\uff1b\u8fd4\u56de\u539f\u5b57\u7b26\u4e32\u7684\u5b50\u5b57\u7b26\u4e32\uff0c\u8be5\u5b57\u7b26\u4e32\u662f\u539f\u5b57\u7b26\u4e32\u4ece<\u59cb>\u4f4d\u7f6e\u5f00\u59cb\uff0c\u957f\u5ea6\u4e3a<\u957f>\u7684\u4e00\u6bb5\u3002\u5982\u679c\u6ca1\u6709\u6307\u5b9a<\u957f>\u6216\u6307\u5b9a\u5f97\u8d85\u8fc7\u5b57\u7b26\u4e32\u957f\u5ea6\uff0c\u5219\u5b50\u5b57\u7b26\u4e32\u4ece<\u59cb>\u4f4d\u7f6e\u4e00\u76f4\u53d6\u5230\u539f\u5b57\u7b26\u4e32\u5c3e\u3002\u5982\u679c\u6240\u6307\u5b9a\u7684\u4f4d\u7f6e\u4e0d\u80fd\u8fd4\u56de\u5b57\u7b26\u4e32\uff0c\u5219\u8fd4\u56de\u7a7a\u5b57\u7b26\u4e32\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 toLowerCase()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.toLowerCase()\uff1b\u8fd4\u56de\u628a\u539f\u5b57\u7b26\u4e32\u6240\u6709\u5927\u5199\u5b57\u6bcd\u90fd\u53d8\u6210\u5c0f\u5199\u7684\u5b57\u7b26\u4e32\u3002<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0 toUpperCase()<\/strong> \u7528\u6cd5\uff1a<\u5b57\u7b26\u4e32\u5bf9\u8c61>.toUpperCase()\uff1b\u8fd4\u56de\u628a\u539f\u5b57\u7b26\u4e32\u6240\u6709\u5c0f\u5199\u5b57\u6bcd\u90fd\u53d8\u6210\u5927\u5199\u7684\u5b57\u7b26\u4e32\u3002<\/span><\/p>\n

 <\/p>\n

Array \u6570\u7ec4\u5bf9\u8c61<\/strong><\/span><\/p>\n

 <\/p>\n

\u6570\u7ec4\u7684\u5b9a\u4e49\u65b9\u6cd5<\/strong>\uff1a<\/span><\/p>\n

 <\/p>\n

\u00a0\u00a0\u00a0<\/span> var <\u6570\u7ec4\u540d> = new Array();
\n<\/span>\u00a0\u00a0\u00a0 \u6dfb\u52a0\u6570\u7ec4\u5143\u7d20\uff1a<\u6570\u7ec4\u540d>[<\u4e0b\u6807>] = ...;<\/p>\n

\u00a0\u00a0\u00a0 \u5728\u5b9a\u4e49\u6570\u7ec4\u7684\u65f6\u5019\u76f4\u63a5\u521d\u59cb\u5316\u6570\u636e\uff1a
\n<\/span>var <\u6570\u7ec4\u540d> = new Array(<\u5143\u7d201>, <\u5143\u7d202>, <\u5143\u7d203>...);<\/span><\/p>\n

\u00a0\u00a0\u00a0 \u4f8b: var myArray = new Array(1, 4.5, 'Hi'); \u3002
\n\u4f46\u662f\uff0c\u5982\u679c\u5143\u7d20\u5217\u8868\u4e2d\u53ea\u6709\u4e00\u4e2a\u5143\u7d20\uff0c\u800c\u8fd9\u4e2a\u5143\u7d20\u53c8\u662f\u4e00\u4e2a\u6b63\u6574\u6570\u7684\u8bdd\uff0c\u8fd9\u5c06\u5b9a\u4e49\u4e00\u4e2a\u5305\u542b
\n<\u6b63\u6574\u6570><\/span><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Number \u201c\u6570\u5b57\u201d\u5bf9\u8c61   \u5c5e\u6027     MAX_VALUE \u7528\u6cd5\uff1aNumber.MAX_VALUE\uff1b\u8fd4\u56de\u201c\u6700\u5927\u503c\u201d\u3002 MIN_VALUE \u7528\u6cd5\uff1aNumber.MIN_VALUE\uff1b\u8fd4\u56de\u201c\u6700\u5c0f\u503c\u201d\u3002 NaN \u7528\u6cd5\uff1aNu…<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-1779","post","type-post","status-publish","format-standard","hentry","category-t"],"_links":{"self":[{"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/posts\/1779","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/comments?post=1779"}],"version-history":[{"count":0,"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/posts\/1779\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/media?parent=1779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/categories?post=1779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.justzz.com\/spec\/wp-json\/wp\/v2\/tags?post=1779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}