// JScript 文件
    var Eval={
    GetTop:function()   //屏幕可视范围离页面顶距离
    {
        if(typeof(window.pageYOffset)!='undefined')
        {
	        return window.pageYOffset;
        }
        else if(typeof(document.compatMode)!='undefined'&&document.compatMode!='BackCompat')
        {
	        return document.documentElement.scrollTop;
        }
        else if(typeof(document.body)!='undefined')
        {
	        return document.body.scrollTop;
        }
    },
    
    GetLeft:function()  //屏幕可视范围离左边距离
    {
        if(typeof(window.pageXOffset)!='undefined')
        {
	        return window.pageXOffset;
        }
        else if(typeof(document.compatMode)!='undefined'&&document.compatMode!='BackCompat')
        {
	        return document.documentElement.scrollLeft;
        }
        else if(typeof(document.body)!='undefined')
        {
	        return document.body.scrollLeft;
        }
    },
    
    GetWidth:function() //屏幕可视范围宽
    {
        if(typeof(document.compatMode)!='undefined'&&document.compatMode!='BackCompat')
        {
	        return document.documentElement.clientWidth;
        }
        else if(typeof(document.body)!='undefined')
        {
	        return document.body.clientWidth;
        }
    },
    
    GetHeight:function()    //屏幕可视范围高
    {
        if(typeof(document.compatMode)!='undefined'&&document.compatMode!='BackCompat')
        {
	        return document.documentElement.clientHeight;
        }
        else if(typeof(document.body)!='undefined')
        {
	        return document.body.clientHeight;
        }
    }
}