{"id":12212,"date":"2021-01-15T00:00:00","date_gmt":"2021-01-14T16:00:00","guid":{"rendered":"https:\/\/fgchen.com\/wpedu2\/2021\/01\/15\/javascript%e5%bf%ab%e9%80%9f%e5%85%a5%e9%96%80-%e5%87%bd%e5%bc%8f%e8%88%87%e5%b7%a5%e5%85%b7%e9%a1%9e%e5%88%a5%e5%ba%ab\/"},"modified":"2026-03-30T14:39:25","modified_gmt":"2026-03-30T06:39:25","slug":"javascript%e5%bf%ab%e9%80%9f%e5%85%a5%e9%96%80-%e5%87%bd%e5%bc%8f%e8%88%87%e5%b7%a5%e5%85%b7%e9%a1%9e%e5%88%a5%e5%ba%ab","status":"publish","type":"post","link":"https:\/\/fgchen.com\/wpedu\/2021\/01\/javascript%e5%bf%ab%e9%80%9f%e5%85%a5%e9%96%80-%e5%87%bd%e5%bc%8f%e8%88%87%e5%b7%a5%e5%85%b7%e9%a1%9e%e5%88%a5%e5%ba%ab\/","title":{"rendered":"JavaScript\u5feb\u901f\u5165\u9580 – \u51fd\u5f0f\u8207\u5de5\u5177\u985e\u5225\u5eab"},"content":{"rendered":"

\u51fd\u5f0f\/Functions\u00a0<\/b><\/h1>\n\n\u51fd\u5f0f\u7684\u5ba3\u544a\u8207\u5b9a\u7fa9\uff1a\n\nfunction \u51fd\u5f0f\u540d\u7a31(\u53c3\u65781, \u53c3\u65782, \u53c3\u65783) {\u00a0<\/b>\n\n\/\/\u51fd\u5f0fbody<\/b>\n\n}\u00a0<\/b>\n\n
function say() {\n   \/\/...\n}\n\nfunction square(a) {\n    \/\/...\n}\n\nfunction add(a, b) {\n   \/\/ ...\n}\n\nfunction say(message) {\n    console.log(message);\n}\n\n<\/pre>\n\n\u51fd\u5f0f\u7684\u547c\u53eb\uff1a\n\nfunctionName(arguments);\n\n
say('Hello');<\/pre>\n\n\u51fd\u5f0f\u7684\u8fd4\u56de\u503c\n\n
function add(a, b) {\n    return a + b;\n}\n\n\/\/\u547c\u53ebadd\u51fd\u5f0f\uff0c\u4e26\u8fd4\u56de\u4e8c\u500b\u53c3\u6578a\u8207b\u503c\u7684\u52a0\u7e3d\nlet sum = add(10, 20);\nconsole.log('Sum:', sum);<\/pre>\n\n
function compare(a, b) {\n    if (a > b) {\n        return -1;\n    } else if (a < b) {\n        return 1;\n    }\n    return 0;\n}<\/pre>\n\n
Function Expressions (\u51fd\u5f0f\u9673\u8ff0)<\/h1>\n\n
let x = function (num) { return num * num };\nconsole.log( x(4) );\n\/\/\u8f38\u51fa\uff1a16\n<\/pre>\n\n
Anonymous Function \u533f\u540d\u51fd\u5f0f<\/h1>\n\n
\u5c31\u5730\u57f7\u884c\u51fd\u5f0f<\/h1>\n\n\u4f8b1\uff1a\n\n(function<\/span>() <\/span>{ console<\/span>.log(‘IIFE’<\/span>); })();\n\n
(function() {\n    console.log('IIFE');\n})();<\/pre>\n\n\u4f8b2\uff1a\n\n
let person = {\n    firstName: 'John',\n    lastName: 'Doe'\n};\n\n(function () {\n    console.log(`${person.firstName} ${person.lastName}`);\n})(person);<\/pre>\n\n
Regular Function\/Inline Function\/Anonymous Function\u5b8c\u6574\u4f8b<\/h1>\n\n
Function<\/h2>\n\n
function func() { \n  alert ('function'); \n} \n$('a').click(func);<\/pre>\n\n
Inline Function<\/h2>\n\n
var func = function() { \n  alert ('inline') \n}; \n\n$('a').click(func); \n\n\/\/ Alternative es6+ inline arrow function. \nlet func2 = () => alert('inline'); \n$('a').click(func2);<\/pre>\n\n
Anonymous Function<\/h2>\n\n
$('a').click(function() { \n  alert('anonymous'); \n}); \n\n\/\/ Alternative es6+ anonymous arrow function. \n$('a').click(() => alert('anonymous'));<\/pre>\n\n
<\/h1>\n\n
\u5de5\u5177\u51fd\u5f0f<\/h1>\n\n
\u8f38\u51fa\u8cc7\u6599\/Outputting Data\u00a0<\/b><\/h2>\n\nalert()\u00a0<\/b>\n\n\u4f7f\u7528\u700f\u89bd\u5668\u7684\u8b66\u544a\u65b9\u584a\u8f38\u51fa\u8a0a\u606f\u3002<\/span>\n\nconfirm()\u00a0<\/b>\n\nOpens up a yes\/no dialog and returns true\/false depending on user click\u00a0<\/span>\n\n\u958b\u555f\u4e00\u500bYes\u6216No\u7684\u5c0d\u8a71\u6846\uff0c\u4e26\u4e14\u4f9d\u4f7f\u7528\u8005\u6309\u4e86Yes\u6216No\u50b3\u56detrue\u6216false\u3002\n\nconsole.log()\u00a0<\/b>\n\nWrites information to the browser console, good for debugging purposes\u00a0 \u5c07\u8cc7\u6599\u5f9e\u700f\u89bd\u5668\u4e2d\u7684console\u5217\u5370\u51fa\u4f86\uff0c\u9069\u5408\u7a0b\u5f0f\u9664\u932f\u4f7f\u7528\u3002<\/span>\n\ndocument.write()\u00a0<\/b>\n\n\u76f4\u63a5\u5c07\u8cc7\u6599\u8f38\u51fa\u5230\u5230HTML\u6587\u4ef6\u4e2d\u3002<\/span>\n\nprompt()\u00a0<\/b>\n\n\u5efa\u7acb\u4e00\u500b\u53d6\u5f97\u4f7f\u7528\u8005\u8f38\u5165\u7684\u5c0d\u8a71\u65b9\u584a\u3002<\/span>\n\n
<\/h2>\n\n
\u5e38\u7528\u5de5\u5177\u51fd\u5f0f\u00a0<\/b><\/h2>\n\ndecodeURI()\u00a0<\/b>\n\n\u89e3\u78bc\u4e00\u500b\u7531encodeURI\u6216\u985e\u4f3c\u65b9\u6cd5\u6240\u89ee\u7acb\u7684URI<\/span>\n\ndecodeURIComponent()\u00a0<\/b>\n\n\u89e3\u78bc\u4e00\u500bURI\u7684\u7d44\u6210<\/span>\n\nencodeURI()\u00a0<\/b>\n\n\u5c07\u4e00\u500bURI\u4ee5UTF-8\u65b9\u5f0f\u7de8\u78bc\n\nencodeURIComponent()\u00a0<\/b>\n\nSame but for URI components\u00a0<\/span>\n\neval()\u00a0<\/b>\n\nEvaluates JavaScript code represented as a string\u00a0<\/span>\n\nisFinite()\u00a0<\/b>\n\nDetermines whether a passed value is a finite number\u00a0<\/span>\n\nisNaN()\u00a0<\/b>\n\nDetermines whether a value is NaN or not\u00a0<\/span>\n\nNumber()\u00a0<\/b>\n\nReturns a number converted from its argument\u00a0<\/span>\n\nparseFloat()\u00a0<\/b>\n\nParses an argument and returns a floating point number\u00a0<\/span>\n\nparseInt()\u00a0<\/b>\n\nParses its argument and returns an integer\u00a0<\/span>\n\n
\u65e5\u671f\u985e\u5225 Date<\/b><\/h1>\n\n
\u65e5\u671f\u7269\u4ef6\u5efa\u7acb<\/h2>\n\nDate()\u00a0<\/b>\n\n\u5efa\u7acb\u4e00\u500b\u76ee\u524d\u65e5\u671f\u8207\u6642\u9593\u7684\u65e5\u671fDate\u7269\u4ef6<\/span>\n\nDate(2017, 5, 21, 3, 23, 10, 0)\u00a0<\/b>\n\n\u5efa\u7acb\u4e00\u500b\u7279\u5b9a\u65e5\u671f\u7269\u4ef6\uff0c\u4e0a\u4f8b\uff1a\u5e74\u3001\u6708\u3001\u65e5\u3001\u6642\u3001\u5206\u3001\u79d2\u3001\u6beb\u79d2<\/span>\n\nDate(“2017-06-23”)\u00a0<\/b>\n\n\u4ee5\u65e5\u671f\u5b57\u4e32\u7684\u65b9\u5f0f\u5efa\u7acb\u4e00\u500b\u65e5\u671f\u7269\u4ef6<\/span>\n\n
\u65e5\u671f\u7269\u4ef6\u7684\u64cd\u4f5c\u00a0<\/b><\/h2>\n\ngetDate()\u00a0<\/b>\n\n\u53d6\u5f97\u65e5\u671f\u7684\u6578\u503c (1-31)\u00a0<\/span>\n\ngetDay()\u00a0<\/b>\n\n\u53d6\u5f97\u79ae\u62dc\u5e7e\u7684\u6578\u503c (0-6)\u00a0<\/span>\n\ngetFullYear()\u00a0<\/b>\n\n\u53d6\u5f974\u4f4d\u6578\u7684\u5e74\u4efd\u6578\u503c (yyyy)\u00a0<\/span>\n\ngetHours()\u00a0<\/b>\n\n\u53d6\u5f97\u6642\u6578 (0-23)\u00a0<\/span>\n\ngetMilliseconds()\u00a0<\/b>\n\n\u53d6\u5f97\u6beb\u79d2\u6578\u503c (0-999)\u00a0<\/span>\n\ngetMinutes()\u00a0<\/b>\n\n\u53d6\u5f97\u5206\u9418\u6578\u503c (0-59)\u00a0<\/span>\n\ngetMonth()\u00a0<\/b>\n\n\u53d6\u5f97\u6708\u6578\u503c (0-11)\u00a0<\/span>\n\ngetSeconds()\u00a0<\/b>\n\n\u53d6\u5f97\u79d2\u6578\u503c (0-59)\u00a0<\/span>\n\ngetTime()\u00a0<\/b>\n\n\u53d6\u5f97\u5f9e1970\/1\/1\u8d77\u7b97\u7684\u6beb\u79d2\u503c<\/span>\n\n
Number\u985e\u5225<\/b><\/h1>\n\n
Number\u503c<\/b><\/h2>\n\nMAX_VALUE\u00a0<\/b>\n\nJavaScript\u6240\u80fd\u8868\u793a\u7684\u6700\u5927\u503c<\/span>\n\nMIN_VALUE\u00a0<\/b>\n\nJavaScript\u6240\u80fd\u8868\u793a\u7684\u6700\u5c0f\u6b63\u6574\u6578\u503c<\/span>\n\nNaN\u00a0<\/b>\n\n\u201cNot-a-Number\u201d\uff0c\u4e0d\u662f\u4e00\u500b\u6578\u503c\u8868\u793a<\/span>\n\nNEGATIVE_INFINITY\u00a0<\/b>\n\nThe negative Infinity value\u00a0 \u8ca0\u7121\u9650\u5927\u503c<\/span>\n\nPOSITIVE_INFINITY\u00a0 \u6b63\u7121\u9650\u5927\u503c<\/b>\n\nPositive Infinity value\u00a0<\/span>\n\n
Number\u65b9\u6cd5<\/b><\/h2>\n\ntoExponential()\u00a0<\/b>\n\n\u5c07\u6578\u5b57\u8f49\u578b\u70ba\u79d1\u5b78\u8a18\u865f\u8868\u793a\u6cd5 (\u5b57\u4e32\u578b\u614b)\u3002\n\n
var numObj = 77.1234;\n\nnumObj.toExponential()  \/\/ 7.71234e+1\nnumObj.toExponential(4) \/\/ 7.7123e+1\nnumObj.toExponential(2) \/\/ 7.71e+1\n(77.1234).toExponential() \/\/ 7.71234e+1\n(77).toExponential()    \/\/ 7.7e+1<\/pre>\n\ntoFixed()\u00a0<\/b>\n\n\u7528\u4f86\u5c07\u4e00\u500b\u6578\u5b57\u8f49\u6210\u56fa\u5b9a\u5c0f\u6578\u4f4d\u6578\u7684\u5b57\u4e32\u3002\n\n
var numObj = 12345.6789;\n\nnumObj.toFixed();       \/\/ '12346'\nnumObj.toFixed(1);      \/\/ '12345.7' \u56db\u6368\u4e94\u5165\nnumObj.toFixed(6);      \/\/ '12345.678900' \u6703\u88dc\u96f6\n(1.23e+20).toFixed(2);  \/\/ '123000000000000000000.00'\n(1.23e-10).toFixed(2);  \/\/ '0.00'\n(2.34).toFixed(1);      \/\/ '2.3'\n(2.35).toFixed(1);      \/\/ '2.4' \u56db\u6368\u4e94\u5165\n(-2.34).toFixed(1);     \/\/ '-2.3'<\/pre>\n\ntoPrecision()\u00a0<\/b>\n\n\u5c07\u6578\u5b57\u683c\u5f0f\u5316\u6210\u6307\u5b9a\u9577\u5ea6\u7684\u5b57\u4e32\uff0c\u5982\u679c\u6578\u5b57\u9577\u5ea6\u5927\u65bc\u6307\u5b9a\u7684\u9577\u5ea6\uff0c\u6703\u7528\u79d1\u5b78\u8868\u793a\u6cd5\u986f\u793a\u3002\n\n
var numObj = 18.456;\nnumObj.toPrecision(1)  \/\/ '2e+1' \u79d1\u5b78\u8868\u793a\u6cd5\nnumObj.toPrecision(2) \/\/ '18'\nnumObj.toPrecision(4) \/\/ '18.46'\nnumObj.toPrecision(6) \/\/ '18.4560' \u88dc\u96f6<\/pre>\n\ntoString()\u00a0<\/b>\n\n\u5c07\u6578\u503c\u8f49\u63db\u70ba\u5b57\u4e32<\/span>\n\nvalueOf()\u00a0<\/b>\n\n\u5c07\u00a0Number \u7269\u4ef6 (Number object)\u00a0\u578b\u614b\u8f49\u578b\u6210\u57fa\u672c\u6578\u503c\u578b\u614b (primitive value)\u3002\n\n
var numObj = new Number(10);\nconsole.log(typeof numObj); \/\/ object\n\nvar num = numObj.valueOf();\nconsole.log(num);           \/\/ 10\nconsole.log(typeof num);    \/\/ number<\/pre>\n\n
Math\u985e\u5225<\/b><\/h1>\n\n
Math\u503c<\/b><\/h2>\n\nE \u81ea\u7136\u5c0d\u6578(natural logarithm) \u7684\u57fa\u5e95(base) \u6216\u7a31\u6b50\u62c9\u5e38\u6578(Euler’s constant)\uff0c\u7d042.718\u3002 <\/b>\n\nLN2 2\u7684\u81ea\u7136\u5c0d\u6578<\/b>\n\nLN10 10\u7684\u81ea\u7136\u5c0d\u6578<\/b>\n\nLOG2E \u4ee52\u70ba\u5e95\u7684e \u7684\u5c0d\u6578 <\/b>\n\nLOG10E \u4ee510\u70ba\u5e95\u7684e \u7684\u5c0d\u6578<\/b>\n\nPI\u00a0 \u5713\u5468\u7387 \u03c0<\/b>\n\n
Math\u65b9\u6cd5<\/b><\/h2>\n\nabs(x)\u00a0<\/b>\n\n\u50b3\u56dex\u7684\u7d55\u5c0d\u503c<\/span>\n\nacos(x)\u00a0<\/b>\n\nasin(x)\u00a0<\/b>\n\natan(x)\u00a0<\/b>\n\natan2(y,x)\u00a0<\/b>\n\nceil(x)\u00a0<\/b>\n\n\u5929\u82b1\u677f\u6578\uff0c\u7121\u689d\u4ef6\u9032\u4f4d\uff0c\u6703\u8fd4\u56de\u5927\u65bc\u7b49\u65bc\u50b3\u5165\u53c3\u6578\u7684\u6700\u5c0f\u6574\u6578\u503c\u3002<\/span>\n\n
Math.ceil(.95);    \/\/ 1\nMath.ceil(4);      \/\/ 4\nMath.ceil(7.004);  \/\/ 8\nMath.ceil(-0.95);  \/\/ -0\nMath.ceil(-4);     \/\/ -4\nMath.ceil(-7.004); \/\/ -7<\/pre>\n\ncos(x)\u00a0<\/b>\n\nexp(x)\u00a0<\/b>\n\nfloor(x)\u00a0<\/b>\n\n\u5730\u677f\u6578\uff0c\u7121\u689d\u4ef6\u6368\u53bb\uff0c\u6703\u8fd4\u56de\u5c0f\u65bc\u7b49\u65bc\u50b3\u5165\u53c3\u6578\u7684\u6700\u5927\u6574\u6578\u503c\u3002<\/span>\n\n
Math.floor( 45.95); \/\/  45\nMath.floor( 45.05); \/\/  45\nMath.floor(  4   ); \/\/   4\nMath.floor(-45.05); \/\/ -46 \nMath.floor(-45.95); \/\/ -46<\/pre>\n\nlog(x)\u00a0<\/b>\n\nmax(x,y,z,…,n)\u00a0<\/b>\n\n\u53d6\u6700\u5927\u6578\u00a0<\/span>\n\nmin(x,y,z,…,n)\u00a0<\/b>\n\n\u53d6\u6700\u5c0f\u503c<\/span>\n\npow(x,y)\u00a0<\/b>\n\n\u4e58\u51aax^y<\/span>\n\nrandom()\u00a0<\/b>\n\n\u96a8\u6a5f\u6578\uff0c\u8fd4\u56de\u4e00\u500b 0 (\u5305\u542b) ~ 1 (\u4e0d\u5305\u542b) \u7684\u96a8\u6a5f\u6578\u3002 0<= r < 1\u3002<\/span>\n\nround(x)\u00a0<\/b>\n\n4\u63685\u5165<\/span>\n\nsin(x)\u00a0<\/b>\n\nThe sine of x (x is in radians)\u00a0<\/span>\n\nsqrt(x)\u00a0<\/b>\n\n\u5e73\u65b9\u6839\u503c\u00a0<\/span>\n\ntan(x)\u00a0<\/b>\n\nThe tangent of an angle\u00a0<\/span>","protected":false},"excerpt":{"rendered":"
\u51fd\u5f0f\/Functions\u00a0 \u51fd\u5f0f\u7684\u5ba3\u544a\u8207\u5b9a\u7fa9\uff1a function \u51fd\u5f0f\u540d\u7a31(\u53c3\u6578 … <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[266],"tags":[],"class_list":["post-12212","post","type-post","status-publish","format-standard","hentry","category-266"],"_links":{"self":[{"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/posts\/12212","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/comments?post=12212"}],"version-history":[{"count":1,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/posts\/12212\/revisions"}],"predecessor-version":[{"id":13282,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/posts\/12212\/revisions\/13282"}],"wp:attachment":[{"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/media?parent=12212"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/categories?post=12212"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fgchen.com\/wpedu\/wp-json\/wp\/v2\/tags?post=12212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}