javascript设置网页刷新或者重新加载后滚动条的位置不变

window.onbeforeunload = function(){
    var scrollPos;    
    if (typeof window.pageYOffset != 'undefined') {
        scrollPos = window.pageYOffset;
    }
    else if (typeof document.compatMode != 'undefined' &&
        document.compatMode != 'BackCompat') {
        scrollPos = document.documentElement.scrollTop;
    }
    else if (typeof document.body != 'undefined') {
        scrollPos = document.body.scrollTop;
    }
    document.cookie="scrollTop="+scrollPos; //存储滚动条位置到cookies中
}

window.onload = function()
{ 
    if(document.cookie.match(/scrollTop=([^;]+)(;|$)/)!=null){
        var arr=document.cookie.match(/scrollTop=([^;]+)(;|$)/); //cookies中不为空，则读取滚动条位置
        document.documentElement.scrollTop=parseInt(arr[1]);
        document.body.scrollTop=parseInt(arr[1]);
    }
}