$(window).scroll(function() {
var scrollTop = $(this).scrollTop();
var scrollHeight = $(document).height();
var windowHeight = $(this).height();
var positionValue = (scrollTop + windowHeight) - scrollHeight;
if (positionValue >= 0) {
//执行ajax，获取数据
}
});
原文：http://www.cnblogs.com/vscss/p/5691244.html