浏览器滚动条触底事件(转)

<script>
//浏览量滚动条触底事件
window.onscroll = function (){
    var marginBot = 0;
    if (document.documentElement.scrollTop){
        var X=document.documentElement.scrollHeight;
        var Y=document.documentElement.scrollTop+document.body.scrollTop;
        var Z=document.documentElement.clientHeight;
        marginBot=X-Y-Z;
    } else {
        var J=document.body.scrollHeight;
        var I=document.body.scrollTop;
        var K=document.body.clientHeight;
        marginBot=J-I-K;
    }
    if(marginBot<=0) {
    //do something
    }
}
</script>