兼容低版本IE的JScript5.5实现

2022-07-15 80酷酷网 80kuku.com

　　js|jscript

作者Blog：

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：

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：

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:

代码拷贝框

/* iecompat.js** Copyright Ma Bingyao <andotujn.edu.cn>* 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 correctObject.prototype.isPrototypeOf = function (o) { return (this.constructor == o.constructor);} // this return value was not very correctObject.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', '%26', "'", '(', ')', '*', '%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 */
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