基于prototype的动态加载js的一个类

1. var LinkFile = Class.create();
3. LinkFile.prototype = {initialize:function (_url, options) {
4.     this.options = Object.extend({type:"script", charset:"", noCache:false, callBack:null}, options || {});
5.     this.options.callBack = Object.extend({variable:null, onLoad:null, timeout:20000, timerStep:500}, options.callBack || {});
6.     this.timer = 0;
7.     this.loadTimer = null;
8.     if (this.options.type == "script") {
9.         //this.getJs(_url.trim());
10.         this.getJs(_url);
11.     } else {
12.         //this.getCss(_url.trim());
13.         this.getCss(_url);
14.     }
15.     if (this.options.callBack.variable) {
16.         this.options.callBack.vars = this.options.callBack.variable.split(".");
17.     }
18. }, stop:function () {
19.     clearInterval(this.loadTimer);
20.     this.loadTimer = null;
21.     this.timer = 0;
22.     return;
23. }, doCallback:function () {
24.     if (this.options.type != "script" || !this.options.callBack || !this.options.callBack.vars || !this.options.callBack.onLoad) {
25.         this.stop();
26.         return;
27.     }
28.     this.timer += this.options.callBack.timerStep;
29.     if ($A(this.options.callBack.vars).any(
30.     function (v, i) {
31.         var _v = this.options.callBack.vars.slice(0, i + 1).join(".");
32.         return (eval("typeof " + _v + "== /"undefined/"") || eval(_v + "==null"));
33.     }.bind(this)) && (this.timer < this.options.callBack.timeout)) {
34.         return;
35.     } else {
36.         clearInterval(this.loadTimer);
37.         if ($A(this.options.callBack.vars).all(function (v, i) {
38.             var _v = this.options.callBack.vars.slice(0, i + 1).join(".");
39.             return (eval("typeof " + _v + "!= /"undefined/"") && eval(_v + "!=null"));
40.         }.bind(this))) {
41.             (this.options.callBack.onLoad)();
42.         } else {
43.             if ((this.timer >= this.options.callBack.timeout) && this.options.callBack.onFailure) {
44.                 (this.options.callBack.onFailure)();
45.             }
46.         }
47.         this.loadTimer = null;
48.         this.timer = 0;
49.     }
50. }, getJs:function (_url) {
51.     var oHead = document.getElementsByTagName("head")[0];
52.     var _links = Element.getChildElementByTagName(oHead, "SCRIPT");
53.     $A(_links).each(function (s) {
54.         if (getFullUrl(s.getAttribute("src") || "") == getFullUrl(_url)) {
55.             Element.remove(s);
56.         }
57.     });
58.     this._link = document.createElement("script");
59.     if (this.options.noCache) {
60.         _url += (_url.match(//?/) ? "&" : "?") + "c=" + timeStamp();
61.     }
62.     this._link.src = _url;
63.     this._link.type = "text/javascript";
64.     if (this.options.charset) {
65.         this._link.charset = this.options.charset;
66.     }
67.     if (this.options.callBack) {
68.         this.loadTimer = setInterval(function () {
69.             this.doCallback();
70.         }.bind(this), this.options.callBack.timerStep);
71.     }
72.     oHead.appendChild(this._link);
73. }, getCss:function (_url) {
74.     var oHead = document.getElementsByTagName("head")[0];
75.     var _links = Element.getChildElementByTagName(oHead, "LINK");
76.     $A(_links).each(function (l) {
77.         if (getFullUrl(l.getAttribute("href") || "") == getFullUrl(_url)) {
78.             Element.remove(l);
79.         }
80.     });
81.     this._link = document.createElement("link");
82.     if (this.options.noCache) {
83.         _url += (_url.match(//?/) ? "&" : "?") + "c=" + timeStamp();
84.     }
85.     this._link.href = _url;
86.     this._link.type = "text/css";
87.     this._link.rel = "stylesheet";
88.     if (this.options.charset) {
89.         this._link.charset = this.options.charset;
90.     }
91.     oHead.appendChild(this._link);
92. }};
93. 
    
    使用方法如下：
    1 ===========
    function search(){
            new LinkFile(url, {
                                            type: 'script',
                                            callBack: {
                                                    variable: 'search_result',
                                                    onLoad: show_result.bind(this),
                                                    onFailure: function(){},
                                                    timeout: 50000
                                                    /*timerStep: 500*/
                                            }});
    }
94. 
    2 ============
    
    function showresult(){
        new LinkFile(commentjspath, {type: 'script',callBack: {variable: 'comments',
                                onLoad: function(){loadJS(commentjspath);showComments(6,1, 6 ,"",<%=articleid%> );},
                               onFailure:function(){document.getElementById("updatecontent").innerHTML="";$("commentCount").innerHTML = "("+0+")"; },
                                timeout: 10000}});
    }