进度条 ，上传遮罩效果

   function coverBody(json){
    //   alert(jQuery(window.document.body));
var bodyScrollSize=getBodyScrollSize();
$(window.document.body).append($("<iframe id='jq_effect_backGroundIframe' style='z-index:1;filter:mask();overflow:hidden;border:0px;margin:0; padding:0;position:absolute;width:"+bodyScrollSize.width+"px;height:"+bodyScrollSize.height+"px;top:0px;left:0px' scrolling='auto' frameborder='0' ></iframe>"));

var jqCover=$("<div id='jq_effect_backGroundDiv'> <div id='jindu'  style='width:368px;height:28px;margin:0 auto;margin-top:165px;'><img src='<%=request.getContextPath()%>/images/jindu.gif' ></div></div>");
var _css = { "background-color":json.color==undefined?"#000":json.color, "position":"absolute","overflow":"hidden", "-moz-opacity": "0.25" , "filter":"alpha(opacity=25)","z-index":"2" ,"opacity":"0.25", "top" : "0px" , "left":"0px","width":bodyScrollSize.width,"height":bodyScrollSize.height };        
jqCover.css(_css);
//jqCover.appendTo("body");
$(window.document.body).append(jqCover);
}



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function getBodyScrollSize()
{
var bodySL, bodyST, bodySW, bodySH;
if(window.pageXOffset)
{
bodySL=window.pageXOffset;
bodySW=window.innerWidth;
bodyST=window.pageYOffset;
bodySH=window.innerHeight;
}
else if(document.documentElement)
{
bodySL=document.documentElement.scrollLeft;
bodySW=document.documentElement.scrollWidth; //-10
bodyST=document.documentElement.scrollTop;
bodySH=document.documentElement.clientHeight>document.documentElement.scrollHeight?document.documentElement.clientHeight:document.documentElement.scrollHeight;
}
else if(document.body)
{
bodySL=document.body.scrollLeft;
bodySW=document.body.scrollWidth;
bodyST=document.body.scrollTop;
bodySH=document.body.clientHeight>document.body.scrollHeight?document.body.clientHeight:document.body.scrollHeight;
}

return {"top":bodyST,"left":bodySL,"width":bodySW,"height":bodySH};
}