自己写了个ScriptLoader

今天写了个ScriptLoader,可以在客户端动态加载Jscript,内部维护了一个Jscript队列,支持向队列里添加\删除Jscript,修改某个Jscript,并且防止了Jscript的重复.
有两种加载模式:
1.加载队列里所有的Jscript;
2.加载某一特定id的Jscript

window.ScriptLoader = new function()
{
    var queuedScripts = new Array();
    var currentScript = null;

    function onScriptLoaded()
    {
        //Load next
        doScriptLoad();            
    }

    function onScriptError()
    {
        //Invoke the error handler
        if (this.errorHandler)
            this.errorHandler.invoke();

        //Load next
        doScriptLoad();
    }

    function onScriptReadyStateChange()
    {
        if(event.srcElement.readyState == "complete" || event.srcElement.readyState == "loaded")
            onScriptLoaded();
    }

    this.loadScript = function(id,scriptPath,scriptText,loadall)
    {
        if(id != null)
            this.addScript(id,scriptPath,scriptText)
        doScriptLoad(id);
    }

    this.addScript = function(id,scriptPath,scriptText)
    {
        for(var i=0; i<queuedScripts.length; i++)
        {
            if(queuedScripts[i].id === id)
            {
                alert("已有相同id的Script Tag");
                break;
            }
        }

        queuedScripts.push(new ScriptBlock(id,scriptPath,scriptText));
    }

    this.alterScript = function(id,scriptPath,scriptText)
    {
        for(var i=0; i<queuedScripts.length; i++)
        {
            if(queuedScripts[i].id === id)
            {
                queuedScripts[i].scriptPath = scriptPath;
                queuedScripts[i].scriptText = scriptText;
                break;
            }
        }
    }

    this.removeScript = function(id)
    {
        for(var i=0; i<queuedScripts.length; i++)
        {
            if(queuedScripts[i].id === id)
            {
                queuedScripts.splice(i,1);
                break;
            }
        }
    }

    //Does the actual script loading
    function doScriptLoad(id)
    {
        if (queuedScripts.length == 0)
            return;

        var obj = null;
        var currentScript = null;
        if(id == null || document.getElementById(id) == null)
        {
            obj = queuedScripts.pop();
            if(obj == null) return;
            currentScript = document.createElement("SCRIPT");
            currentScript.id = obj.id;
            currentScript.type = "text/javascript";
            currentScript.onload = onScriptLoaded; //For Mozilla/Opera
            currentScript.onerror = onScriptError; //For Mozilla/Opera
            currentScript.onreadystatechange = onScriptReadyStateChange; //For IE
            document.getElementsByTagName('head')[0].appendChild(currentScript);
        }
        else
        {
            currentScript = document.getElementById(id);
            if(currentScript.tagName != "SCRIPT")
            {
                alert("有相同id的不同类型元素存在");
                return;
            }

            for(var i=0; i<queuedScripts.length; i++)
            {
                if(queuedScripts[i].id === id)
                {
                    obj = queuedScripts[i];
                    break;
                }
                if(obj == null) return;
            }
        }
        currentScript.src = obj.scriptPath;
        currentScript.text = obj.scriptText;
    }
}
function ScriptBlock(id,scriptPath,scriptText)
{
    if(scriptPath == null)scriptPath = "";
    if(scriptText == null)scriptText = "";
    this.id = id;
    this.scr = scriptPath;
    this.text = scriptText;
}

拙作旨在抛砖引玉..