js获取浏览器滚动条距离顶端的距离

//回到页面顶部  
    $("#goTotop").click(function(){  
        $(‘body,html‘).animate({scrollTop:0},1500); //点击按钮让其回到页面顶部  
    });  
      
    $(window).scroll(function() {  
        var yheight1=window.pageYOffset; //滚动条距顶端的距离  
        var yheight=getScrollTop(); //滚动条距顶端的距离  
        var height =document.documentElement.clientHeight//浏览器可视化窗口的大小  
        var top=parseInt(yheight)+parseInt(height)-217;  
        var divobj=$(".kf");  
        divobj.attr(‘style‘,‘top:‘+top+‘px;‘);  
    })  
      
/** 
 * 获取滚动条距离顶端的距离 
 * @return {}支持IE6 
 */  
function getScrollTop() {  
        var scrollPos;  
        if (window.pageYOffset) {  
        scrollPos = window.pageYOffset; }  
        else if (document.compatMode && document.compatMode != ‘BackCompat‘)  
        { scrollPos = document.documentElement.scrollTop; }  
        else if (document.body) { scrollPos = document.body.scrollTop; }   
        return scrollPos;   
}