function getClientHeight()
{
    //可见高
    var clientHeight=document.body.clientHeight;//其它浏览器默认值
    if(navigator.userAgent.indexOf("MSIE 6.0")!=-1)
    {
        clientHeight=document.body.clientHeight;
    }
    else if(navigator.userAgent.indexOf("MSIE")!=-1)
    {
        //IE7 IE8
        clientHeight=document.documentElement.offsetHeight
    }

    if(navigator.userAgent.indexOf("Chrome")!=-1)
    {
        clientHeight=document.body.scrollHeight;
    }

    if(navigator.userAgent.indexOf("Firefox")!=-1)
    {
        clientHeight=document.documentElement.scrollHeight;
    }
    return clientHeight;
}

//获得网页内容高度
function getContentHeight()
{
    //可见高
    var ContentHeight=document.body.scrollHeight;//其它浏览器默认值

    if(navigator.userAgent.indexOf("Chrome")!=-1)
    {
        ContentHeight= document.body.clientHeight;
    }

    if(navigator.userAgent.indexOf("Firefox")!=-1)
    {
        ContentHeight=document.body.offsetHeight;
    }
    return ContentHeight;
}