每日一库：classList.js
地址：https://github.com/eligrey/classList.js
疑问：
function Ctor(){
}
Ctor.prototype = [];
Ctor.prototype.show = function (){
console.log(this.join(''));
}
var c = new Ctor();
c.push('a');
c.push('b');
c.show();
ie下为什么不行？
源码：
<!doctype html>
<html>
<head>
<meta charset="gb2312" />
<title></title>
<meta name="description" content=" ">
<meta name="keywords" content=" ">
</head>
<body>
<!--header-->
<style>
.cls1{background-color:blue;}
.cls2{background-color:red;}
.cls3{background-color:green;}
</style>
<div id="test">aaa </div>
<script>
/*
* classList.js: Cross-browser full element.classList implementation.
* 2012-11-15
*
* By Eli Grey, http://eligrey.com
* Public Domain.
* NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
*/
/*global self, document, DOMException */
/*! @source http://purl.eligrey.com/github/classList.js/blob/master/classList.js*/
if (typeof document !== "undefined" && !("classList" in document.createElement("a"))) {
(function (view) {
"use strict";
if (!('HTMLElement' in view) && !('Element' in view)) return;
var classListProp = "classList",
protoProp = "prototype" ,
elemCtrProto = (view.HTMLElement || view.Element)[protoProp],
objCtr = Object,
strTrim = String[protoProp].trim || function () {
return this.replace(/^\s+|\s+$/g, "");
},
arrIndexOf = Array[protoProp].indexOf || function (item) {
var i = 0,
len = this.length;
for (; i < len; i++) {
if (i in this && this[i] === item) {
return i;
}
}
return -1;
},
// Vendors: please allow content code to instantiate DOMExceptions
DOMEx = function (type, message) {
this.name = type;
this.code = DOMException[type];
this.message = message;
},
checkTokenAndGetIndex = function (classList, token) {
if (token === "") {
throw new DOMEx(
"SYNTAX_ERR" ,
"An invalid or illegal string was specified"
);
}
if (/\s/.test(token)) {
throw new DOMEx(
"INVALID_CHARACTER_ERR" ,
"String contains an invalid character"
);
}
return arrIndexOf.call(classList, token);
},
ClassList = function (elem) {
var trimmedClasses = strTrim.call(elem.className),
classes = trimmedClasses ? trimmedClasses.split(/\s+/) : [],
i = 0,
len = classes.length ;
for (; i < len; i++) {
this.push(classes[i]);
}
this._updateClassName = function () {
elem.className = this.toString();
};
},
classListProto = ClassList[protoProp] = [], //继承自数组
classListGetter = function () {
return new ClassList(this); //this elem
};
// Most DOMException implementations don't allow calling DOMException's toString()
// on non-DOMExceptions. Error's toString() is sufficient here. 足够的，充足的；[逻辑学]（条件）必然的；〈古〉有能力的，能胜任的，够资格的
DOMEx[protoProp] = Error[protoProp];
classListProto.item = function (i) {
return this[i] || null;
};
classListProto.contains = function (token) {
token += "";
return checkTokenAndGetIndex(this, token) !== -1;
};
classListProto.add = function () {
var tokens = arguments,
i = 0,
l = tokens.length,
token,
updated = false;
do {
token = tokens[i] + "";
if (checkTokenAndGetIndex(this, token) === -1) {
this.push(token);
updated = true;
}
}
while (++i < l);
if (updated) {
this._updateClassName();
}
};
classListProto.remove = function () {
var tokens = arguments,
i = 0,
l = tokens.length,
token ,
updated = false;
do {
token = tokens[i] + "";
var index = checkTokenAndGetIndex(this, token);
if (index !== -1) {
this.splice(index, 1);
updated = true;
}
}
while (++i < l);
if (updated) {
this._updateClassName();
}
};
classListProto.toggle = function (token, forse) {
token += "";
var result = this.contains(token),
method = result ? forse !== true && "remove":forse !== false && "add";
if (method) {
this[method](token);
}
return result;
};
classListProto.toString = function () {
return this.join(" ");
};
if (objCtr.defineProperty) {
var classListPropDesc = {
get: classListGetter,
enumerable: true,
configurable: true
};
try {
objCtr.defineProperty(elemCtrProto, classListProp, classListPropDesc);
} catch (ex) { // IE 8 doesn't support enumerable:true
if (ex.number === -0x7FF5EC54) {
classListPropDesc.enumerable = false;
objCtr.defineProperty(elemCtrProto, classListProp, classListPropDesc);
}
}
} else if (objCtr[protoProp].__defineGetter__) {
elemCtrProto.__defineGetter__(classListProp, classListGetter);
}
}(self));
}
</script>
<!--/header-->
</body>
</html>
