$(window).bind("scroll", function () {
    if(getScrollHeight() == getDocumentTop() + getWindowHeight()){
        //当滚动条到底时,触发内容
        //ajax_function()            
        alert("滑动到的底部");
    }
});

//文档高度
function getDocumentTop() {
    var scrollTop =  0, bodyScrollTop = 0, documentScrollTop = 0;
    if (document.body) {
        bodyScrollTop = document.body.scrollTop;
    }
    if (document.documentElement) {
        documentScrollTop = document.documentElement.scrollTop;
    }
    scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;
    console.log("文档高度scrollTop:"+scrollTop);
    return scrollTop;
}

//可视窗口高度
function getWindowHeight() {
    var windowHeight = 0;
    if (document.compatMode == "CSS1Compat") {
        windowHeight = document.documentElement.clientHeight;
    } else {
        windowHeight = document.body.clientHeight;
    }
    console.log("可视窗口windowHeight:"+windowHeight);
    return windowHeight;
}

//滚动条滚动高度
function getScrollHeight() {
    var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;
    if (document.body) {
        bodyScrollHeight = document.body.scrollHeight;
    }
    if (document.documentElement) {
        documentScrollHeight = document.documentElement.scrollHeight;
    }
    scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;
    console.log("滚动高度scrollHeight:"+scrollHeight);
    return scrollHeight;
}

移动端页面滚动到底部自动加载数据