js上传文件类

var jsUpload = new function(){
    this.hiddenFrameId = 'js_upload_frame';
    this.uploadCallBack;
    this.getHiddenFrame = function(){
        if(this.loginWin==null){
            this.loginWin=document.getElementById(this.hiddenFrameId);
        }
        if(this.loginWin==null){
            var div=document.createElement("div");
            div.id="material_upload_frame_container";
            div.style.display="none";
            document.body.appendChild(div);
            var frameHtml='+</span><span style="color:#0000FF;">this</span><span style="color:#0000CC;">.</span>hiddenFrameId<span style="color:#0000CC;">+</span><span style="color:#FF00FF;">'" id="'</span><span style="color:#0000CC;">+</span><span style="color:#0000FF;">this</span><span style="color:#0000CC;">.</span>hiddenFrameId<span style="color:#0000CC;">+</span><span style="color:#FF00FF;">'" '</span><span style="color:#0000CC;">;</span><br />
			</li>
			<li>
				&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;frameHtml<span style="color:#0000CC;">+</span><span style="color:#0000CC;">=</span><span style="color:#FF00FF;">'width=0 height=0 style="display:none;" onload="jsUpload.frameCallback()">';
            div.innerHTML=frameHtml;
            this.loginWin=document.getElementById(this.hiddenFrameId);
        }
        return this.loginWin
    }
    this.frameCallback = function(json){
        var logWin=document.getElementById(this.hiddenFrameId),response="";
        if(json){
            response=json
        }else{
            try{
                response=logWin.contentWindow.document.body.innerHTML
            }catch(e){
                location.reload()
            }
        }
        if(response!=""&&response.length<6000){
            pos1=response.indexOf("{");
            pos2=response.lastIndexOf("}");
            if(pos1>=0&&pos2>0){
                response=response.substring(pos1,pos2+1)
            }else{
                response="{}"
            }
            var result={},param={};
            response=response.replace(/\r/g,"").replace(/\n/g,"");
            try{
                eval("result="+response)
            }catch(e){
            }
            if (typeof this.uploadCallBack=='function') {
                this.uploadCallBack(result);
            } else {
                if(result['errno']!=0){
                    alert(result['errmsg']);
                }
            }
        }
    }
    this.setUploadCallBack = function(func){
        this.uploadCallBack = func;
    }
    this.upload = function(form, callback){
        if (typeof callback=='function'){
            this.setUploadCallBack(callback);
        }
        this.getHiddenFrame();
        form.target = this.hiddenFrameId;
        form.submit();
    }
};