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兼容低版本IE的JScript5.5实现

摘要: 兼容低版本IE的JScript5.5实现
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作者Blog:www.coolcode.cn

IE 5.5 中的 JScript 版本是 5.5 版,它比以前版本的 JScript 中多了如数组的 push、pop、shift、unshift 方法和 encodeURI、decodeURI 等一些重要的函数。而这些增加的内容在目前其他浏览器(如 Moziila/Firefox 和 Opera)上也同样支持。因此目前开发网站一般对于 IE 浏览器只能兼容到 5.5 版,而对于更低版本的 IE(如 IE 5、IE 4 等),则不再去考虑了。虽然这些低版本的 IE 浏览器目前已经不是主流,但如果能够不需要修改现有代码就能够兼容它们的话,倒是也可以考虑。因此我做了这个兼容低版本 IE 的 JScript 5.5 实现。当然它不可能完全兼容 JScript 5.5,但对于最常用的一些方法,都已经实现了。

该库使用非常简单,只需要在网页的 head 部分加入:

<script type="text/javascript" src="iecompat.js"></script>

就可以了。

完全实现的:

Array 对象中:

·push 方法
·pop 方法
·shift 方法
·unshift 方法
·splice 方法

Date 对象中:

·toDateString 方法
·toTimeString 方法
·toLocaleDateString 方法
·toLocaleTimeString 方法
·Function 对象中:
·apply 方法
·call 方法

Global 对象中:

·undefined 属性
·encodeURI 方法
·encodeURIComponent 方法
·decodeURI 方法
·decodeURIComponent 方法

Number 对象中:

·toExponential 方法
·toFixed 方法
·toPrecision 方法

对于错误处理,IE 5(JScript 5)中已经有了 try…catch 和 throw 语句,因此 decodeURI、decodeURIComponent、toExponential、toFixed、toPrecision、apply 如果出现运行期错误,在 IE 5 上会抛出跟 IE 5.5+ 中一样的错误信息,但是因为 IE 4 没有错误处理语句,如果上述函数出现运行期错误,将会返回 null。注意上面说的运行期错误,不是指上述函数实现中的错误,而是指在这些函数正常工作的情况下应该出现的错误。

其中 Function 的 apply 函数的实现参考了:
http://www.openjsan.org/doc/a/ad/adamk/Upgrade/0.04/lib/Upgrade/Function/apply.html
这段程序。

不完全实现的:

Error 对象

Object 对象中:

·isPrototypeOf 方法
·hasOwnProperty 方法
·propertyIsEnumerable 方法

String 对象中:

·toLocaleLowerCase 方法
·toLocaleUpperCase 方法
·localeCompare 方法

因为 IE 4 不具备错误处理语句,因此 Error 对象在 IE 4 上并不具备 IE 5 以上 Error 对象应具有的功能,因此它对于 IE 4 的实现只能保证你在访问或创建它时不会出错。

Object 中的 isPrototypeOf、hasOwnProperty 和 propertyIsEnumerable 方法只是做了模拟实现,其返回值并非总是正确。

String 对象中的 toLocaleLowerCase、toLocaleUpperCase 和 localeCompare 方法实际上并没有考虑本地字符集,但在大部分系统上它还是工作正常的。

完全没有实现的:

正则表达式对象中扩充的属性和限定符

下载: iecompat.js

代码拷贝框

<textarea class=codeTextarea style="WIDTH: 525px; HEIGHT: 223px" rows=13 cols=73>/* iecompat.js * * Copyright Ma Bingyao * Version: 1.3 * LastModified: 2006-06-18 * This library is free. You can redistribute it and/or modify it. * http://www.coolcode.cn/?p=126 */ /*@cc_on @*/ /*@if (@_jscript_version < 5) function Error(number, description) { if (!number) this.number = 0; else this.number = number; if (!description) this.description = ""; else this.description = description; } @end @*/ /*@if (@_jscript_version < 5.5) // this return value was not very correct Object.prototype.isPrototypeOf = function (o) { return (this.constructor == o.constructor); } // this return value was not very correct Object.prototype.hasOwnProperty = function (proName) { return (typeof(eval("this." + proName)) != "undefind"); } Object.prototype.propertyIsEnumerable = function (proName) { for (var o in this) { if ((proName == o.toString()) && (proName != "propertyIsEnumerable") && (proName != "isPrototypeOf") && (proName != "hasOwnProperty")) return true; } return false; } Error.prototype.message = ""; Error.prototype.name = "Error"; Date.prototype.toDateString = function () { var s = this.toString().split(' '); return [s[0], s[1], s[2], s[5]].join(' '); } Date.prototype.toTimeString = function () { var s = this.toString().split(' '); return [s[3], s[4]].join(' '); } Date.prototype.toLocaleDateString = function () { return this.toLocaleString().split(' ')[0]; } Date.prototype.toLocaleTimeString = function () { return this.toLocaleString().split(' ')[1]; } String.prototype.toLocaleLowerCase = function () { return this.toLowerCase(); } String.prototype.toLocaleUpperCase = function () { return this.toUpperCase(); } String.prototype.localeCompare = function (str) { if (this > str) return 1; if (this < str) return -1; return 0; } Number.prototype.toExponential = function (n) { function repeat(s, n) { var out = ""; for (var i = 0; i < n; i++) { out += s; } return out; } if (!n) { n = 0; } else { n = parseInt(n); if (n < 0 || n > 20) { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823262, "The number of fractional digits is out of range"); e.name = "RangeError"; e.message = e.description; throw(e); @end } } var s, d, e, len; s = this.toString().split("e"); d = parseFloat(s[0]); e = 0; if (typeof(s[1]) != "undefined") { e = parseInt(s[1]); } s = d.toString().split("."); if (typeof(s[1]) != "undefined") { e = e - s[1].length; d = s[0] + s[1]; d = d.replace(/^0+/g, ""); if (d == "") d = "0"; } s = d.toString(); len = s.length - 1; e += len; if (len < n) { s += repeat("0", n - len); } else if (len > n) { s = Math.round(parseFloat("." + s) * Math.pow(10, n + 1)).toString(); if ((s.length - 1) > n) { e += 1; s = Math.round(parseFloat("." + s) * Math.pow(10, n + 1)).toString(); } } if (e >= 0) { e = "+" + e; } if (n == 0) { return s + "e" + e; } else { return s.substr(0, 1) + "." + s.substr(1) + "e" + e; } } Number.prototype.toFixed = function (n) { function repeat(s, n) { var out = ""; for (var i = 0; i < n; i++) { out += s; } return out; } if (!n) { n = 0; } else { n = parseInt(n); if (n < 0 || n > 20) { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823262, "The number of fractional digits is out of range"); e.name = "RangeError"; e.message = e.description; throw(e); @end } } var s, d, e, len; s = this.toString().split("e"); d = parseFloat(s[0]); e = 0; if (typeof(s[1]) != "undefined") { e = parseInt(s[1]); } s = d.toString().split("."); if (typeof(s[1]) != "undefined") { e = e - s[1].length; d = s[0] + s[1]; d = d.replace(/^0+/g, ""); if (d == "") d = "0"; } s = d.toString(); len = s.length - 1; if (e >= 0) { s += repeat("0", e); if (n > 0) { s += "." + repeat("0", n); } } else if (-e <= n) { s = repeat("0", 1 - e - s.length) + s; s = s.substr(0, s.length + e) + "." + s.substr(s.length + e) + repeat("0", n + e); } else { s = repeat("0", 1 - e - s.length) + s; d = parseFloat(s.substr(0, s.length + e) + "." + s.substr(s.length + e)); s = Math.round(d * Math.pow(10, n)).toString(); if (n > 0) { s = repeat("0", n - s.length + 1) + s; s = s.substr(0, s.length - n) + "." + s.substr(s.length - n); } } return s; } Number.prototype.toPrecision = function (n) { function repeat(s, n) { var out = ""; for (var i = 0; i < n; i++) { out += s; } return out; } if (typeof(n) == "undefined") { return this.toString(); } else { n = parseInt(n); if (n < 1 || n > 21) { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823262, "The precision is out of range"); e.name = "RangeError"; e.message = e.description; throw(e); @end } } if (this.valueOf() == 0) { if (n == 1) return "0"; return "0." + repeat("0", n - 1); } var s, d, e, len; s = this.toString().split("e"); d = parseFloat(s[0]); e = 0; if (typeof(s[1]) != "undefined") { e = parseInt(s[1]); } s = d.toString().split("."); if (typeof(s[1]) != "undefined") { e = e - s[1].length; d = s[0] + s[1]; d = d.replace(/^0+/g, ""); if (d == "") d = "0"; } s = d.toString(); len = s.length; d = parseFloat("." + s) * Math.pow(10, n); s = Math.round(d).toString(); if (s.length > parseInt(d).toString().length) { e++; s = s.slice(0, -1); } e += len - s.length; len = s.length; e += len - 1; if (e < n && e > -7) { if ((e < n - 1) && (e > 0)) { s = s.substr(0, e + 1) + "." + s.substr(e + 1); } else if (e <= 0) { s = repeat("0", - e) + s; s = s.substr(0, 1) + "." + s.substr(1); } } else { if (len < n) { s += repeat("0", n - len); } if (e >= 0) { e = "+" + e; } if (n == 1) { s += "e" + e; } else { s = s.substr(0, 1) + "." + s.substr(1) + "e" + e; } } return s; } var undefined; function encodeURI(str) { var l = ['%00', '%01', '%02', '%03', '%04', '%05', '%06', '%07', '%08', '%09', '%0A', '%0B', '%0C', '%0D', '%0E', '%0F', '%10', '%11', '%12', '%13', '%14', '%15', '%16', '%17', '%18', '%19', '%1A', '%1B', '%1C', '%1D', '%1E', '%1F', '%20', '!', '%22', '#', '$', '%25', '&', "'", '(', ')', '*', '+', ',', '-', '.', '/', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', ':', ';', '%3C', '=', '%3E', '?', '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '%5B', '%5C', '%5D', '%5E', '_', '%60', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '%7B', '%7C', '%7D', '~', '%7F']; var out, i, j, len, c, c2; out = []; len = str.length; for (i = 0, j = 0; i < len; i++) { c = str.charCodeAt(i); if (c <= 0x007F) { out[j++] = l[c]; continue; } else if (c <= 0x7FF) { out[j++] = '%' + (0xC0 | ((c >> 6) & 0x1F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ( c & 0x3F)).toString(16).toUpperCase(); continue; } else if (c < 0xD800 || c > 0xDFFF) { out[j++] = '%' + (0xE0 | ((c >> 12) & 0x0F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >> 6) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | (c & 0x3F)).toString(16).toUpperCase(); continue; } else { if (++i < len) { c2 = str.charCodeAt(i); if (c <= 0xDBFF && 0xDC00 <= c2 && c2 <= 0xDFFF) { c = ((c & 0x03FF) << 10 | (c2 & 0x03FF)) + 0x010000; if (0x010000 <= c && c <= 0x10FFFF) { out[j++] = '%' + (0xF0 | ((c >>> 18) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >>> 12) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >>> 6) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | (c & 0x3F)).toString(16).toUpperCase(); continue; } } } } @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823264, "The URI to be encoded contains an invalid character"); e.name = "URIError"; e.message = e.description; throw(e); @end } return out.join(''); } function encodeURIComponent(str) { var l = ['%00', '%01', '%02', '%03', '%04', '%05', '%06', '%07', '%08', '%09', '%0A', '%0B', '%0C', '%0D', '%0E', '%0F', '%10', '%11', '%12', '%13', '%14', '%15', '%16', '%17', '%18', '%19', '%1A', '%1B', '%1C', '%1D', '%1E', '%1F', '%20', '!', '%22', '%23', '%24', '%25', '&', "'", '(', ')', '*', '%2B', '%2C', '-', '.', '%2F', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '%3A', '%3B', '%3C', '%3D', '%3E', '%3F', '%40', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '%5B', '%5C', '%5D', '%5E', '_', '%60', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '%7B', '%7C', '%7D', '~', '%7F']; var out, i, j, len, c; out = []; len = str.length; for(i = 0, j = 0; i < len; i++) { c = str.charCodeAt(i); if (c <= 0x007F) { out[j++] = l[c]; continue; } else if (c <= 0x7FF) { out[j++] = '%' + (0xC0 | ((c >> 6) & 0x1F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ( c & 0x3F)).toString(16).toUpperCase(); continue; } else if (c < 0xD800 || c > 0xDFFF) { out[j++] = '%' + (0xE0 | ((c >> 12) & 0x0F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >> 6) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | (c & 0x3F)).toString(16).toUpperCase(); continue; } else { if (++i < len) { c2 = str.charCodeAt(i); if (c <= 0xDBFF && 0xDC00 <= c2 && c2 <= 0xDFFF) { c = ((c & 0x03FF) << 10 | (c2 & 0x03FF)) + 0x010000; if (0x010000 <= c && c <= 0x10FFFF) { out[j++] = '%' + (0xF0 | ((c >>> 18) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >>> 12) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | ((c >>> 6) & 0x3F)).toString(16).toUpperCase(); out[j++] = '%' + (0x80 | (c & 0x3F)).toString(16).toUpperCase(); continue; } } } } @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823264, "The URI to be encoded contains an invalid character"); e.name = "URIError"; e.message = e.description; throw(e); @end } return out.join(''); } function decodeURI(str) { function throwerror() { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823263, "The URI to be decoded is not a valid encoding"); e.name = "URIError"; e.message = e.description; throw(e); @end } function checkcode() { var d1, d2; d1 = str.charAt(i++); d2 = str.charAt(i++); if (isNaN(parseInt(d1, 16)) || isNaN(parseInt(d2, 16))) { return throwerror(); } return parseInt(d1 + d2, 16); } function checkutf8() { var c = str.charCodeAt(i++); if (c == 37) { if ((c = checkcode()) == null) return null; } if ((c >> 6) != 2) { return throwerror(); } } var out, i, j, len; var c, c2, c3, c4, s; out = []; len = str.length; i = j = 0; while(i < len) { c = str.charCodeAt(i++); if (c == 37) { if ((c = checkcode()) == null) return null; } else { out[j++] = String.fromCharCode(c); continue; } switch(c) { case 35: case 36: case 38: case 43: case 44: case 47: case 58: case 59: case 61: case 63: case 64: { if (str.charCodeAt(i - 3) == 37) { out[j++] = str.substr(i - 3, 3); } else { out[j++] = str.substr(i - 1, 1); } break; } default: { switch (c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: { // 0xxxxxxx out[j++] = String.fromCharCode(c); break; } case 12: case 13: { // 110x xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; out[j++] = String.fromCharCode(((c & 0x1F) << 6) | (c2 & 0x3F)); break; } case 14: { // 1110 xxxx 10xx xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; if ((c3 = checkutf8()) == null) return null; out[j++] = String.fromCharCode(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break; } default: { switch (c & 0xf) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: { // 1111 0xxx 10xx xxxx 10xx xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; if ((c3 = checkutf8()) == null) return null; if ((c4 = checkutf8()) == null) return null; s = ((c & 0x07) << 18) | ((c2 & 0x3f) << 12) | ((c3 & 0x3f) << 6) | (c4 & 0x3f) - 0x10000; if (0 <= s && s <= 0xfffff) { out[j++] = String.fromCharCode(((s >>> 10) & 0x03ff) | 0xd800, (s & 0x03ff) | 0xdc00); } else { return throwerror(); } break; } default: { return throwerror(); } } } } } } } return out.join(''); } function decodeURIComponent(str) { function throwerror() { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823263, "The URI to be decoded is not a valid encoding"); e.name = "URIError"; e.message = e.description; throw(e); @end } function checkcode() { var d1, d2; d1 = str.charAt(i++); d2 = str.charAt(i++); if (isNaN(parseInt(d1, 16)) || isNaN(parseInt(d2, 16))) { return throwerror(); } return parseInt(d1 + d2, 16); } function checkutf8() { var c = str.charCodeAt(i++); if (c == 37) { if ((c = checkcode()) == null) return null; } if ((c >> 6) != 2) { return throwerror(); } } var out, i, j, len; var c, c2, c3, c4, s; out = []; len = str.length; i = j = 0; while(i < len) { c = str.charCodeAt(i++); if (c == 37) { if ((c = checkcode()) == null) return null; } else { out[j++] = String.fromCharCode(c); continue; } switch(c >> 4) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: { // 0xxxxxxx out[j++] = String.fromCharCode(c); break; } case 12: case 13: { // 110x xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; out[j++] = String.fromCharCode(((c & 0x1F) << 6) | (c2 & 0x3F)); break; } case 14: { // 1110 xxxx 10xx xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; if ((c3 = checkutf8()) == null) return null; out[j++] = String.fromCharCode(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break; } default: { switch (c & 0xf) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: { // 1111 0xxx 10xx xxxx 10xx xxxx 10xx xxxx if ((c2 = checkutf8()) == null) return null; if ((c3 = checkutf8()) == null) return null; if ((c4 = checkutf8()) == null) return null; s = ((c & 0x07) << 18) | ((c2 & 0x3f) << 12) | ((c3 & 0x3f) << 6) | (c4 & 0x3f) - 0x10000; if (0 <= s && s <= 0xfffff) { out[j++] = String.fromCharCode(((s >>> 10) & 0x03ff) | 0xd800, (s & 0x03ff) | 0xdc00); } else { return throwerror(); } break; } default: { return throwerror(); } } } } } return out.join(''); } Array.prototype.push = function () { var curlen = this.length; for (var i = 0; i < arguments.length; i++) { this[curlen + i] = arguments[i]; } return this.length; } Array.prototype.pop = function () { var returnValue = this[this.length - 1]; this.length--; return returnValue; } Array.prototype.shift = function () { var returnValue = this[0]; for (var i = 1; i < this.length; i++) { this[i - 1] = this[i]; } this.length--; return returnValue; } Array.prototype.unshift = function () { var curlen = this.length; var arglen = arguments.length; for (var i = curlen - 1; i >= 0 ; i--) { this[i + arglen] = this[i] ; } for (var i = 0; i < arglen; i++) { this[i] = arguments[i]; } //return this.length; // return this value is Gecko/Opera implementation. but IE don't return anything. } Array.prototype.splice = function () { var start = arguments[0]; var deleteCount = arguments[1]; var len = arguments.length - 2; var returnValue = this.slice(start); for (var i = 0; i < len; i++) { this[start + i] = arguments[i + 2]; } for (var i = 0; i < returnValue.length - deleteCount; i++) { this[start + len + i] = returnValue[deleteCount + i]; } this.length = start + len + returnValue.length - deleteCount; returnValue.length = deleteCount; return returnValue; } Function.prototype.apply = function (o, p) { var ps = []; if (typeof(o) == "undefined") { var __$$apply$$__ = this; return eval('__$$apply$$__(' + ps.join(', ') + ');'); } if (p) { if (typeof(p[0]) == "undefined") { @if (@_jscript_version < 5) return null; @else var e = new Error(-2146823260, "Array or arguments object expected"); e.name = "TypeError"; e.message = e.description; throw(e); @end } for (var i = 0; i < p.length; i++) { ps[i] = 'p[' + i + ']'; } } if ((typeof(o) == "object") || (typeof(o) == "function")) { o.__$$apply$$__ = this; var returnValue = eval('o.__$$apply$$__(' + ps.join(', ') + ');'); o.__$$apply$$__ = null; return returnValue; } else { this.__$$apply$$__ = this; var returnValue = eval('this.__$$apply$$__(' + ps.join(', ') + ');'); this.__$$apply$$__ = null; return returnValue; } } Function.prototype.call = function (o) { var ps = []; if (typeof(o) == "undefined") { var __$$call$$__ = this; return eval('__$$call$$__(' + ps.join(', ') + ');'); } if (arguments.length > 1) { for (var i = 1; i < arguments.length; i++) { ps[i - 1] = 'arguments[' + i + ']'; } } if ((typeof(o) == "object") || (typeof(o) == "function")) { o.__$$call$$__ = this; var returnValue = eval('o.__$$call$$__(' + ps.join(', ') + ');'); o.__$$call$$__ = null; return returnValue; } else { this.__$$call$$__ = this; var returnValue = eval('this.__$$call$$__(' + ps.join(', ') + ');'); this.__$$call$$__ = null; return returnValue; } } @end @*/ </textarea>
[Ctrl+A 全部选择 然后拷贝]

如果你想测试低版本的 IE 浏览器上的效果,又没有安装低版本的 IE 浏览器,可以使用这个包:ie_all.zip 。这里面都是不需要安装的 IE,直接释放压缩包到一个目录下,就可以运行了。如果你是 win9x 系统,可以到 这里 下载 win9x 版的 standalone IE。

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