$(window).bind("scroll", function(){
var top = $(this).scrollTop()// 当前窗口的滚动距离
})
如果使用原生js，可以这样写（摘自网上的）：
/**
* 获取滚动条距离顶端的距离
* @return {}支持IE6
*/
function getScrollTop() {
var scrollPos
if (window.pageYOffset) {
scrollPos = window.pageYOffset}
else if (document.compatMode &&document.compatMode != 'BackCompat')
{ scrollPos = document.documentElement.scrollTop}
else if (document.body) { scrollPos = document.body.scrollTop}
return scrollPos
}
var flag = true$(window).scroll(function () {
var me = $(this), div1 = $('#div1')
var scrollTop = me.scrollTop()
var scrollHeight = $(document).height()
var windowHeight = me.height()
if(((scrollHeight - scrollTop - windowHeight) <= 100) &&flag){
div1.click()
flag = false
}else{
flag = true
}
})
