原生js触碰到底部触发函数；

 ?/** ?function __morebook(){ ???console.log(123) ?} ?ScrollBottom(function(){__morebook();}); ?**/ ?//如果直接写一个如下: ?// ?ScrollBottom 方法里有个参数x，x作为函数带参数。然后通过doFun去调用； ?// ?为何doFun做为参数也调用了，是因为方法里有个setTimeOut; ?// ?这样写的意义是什么呢？是将scrollBottom写成公用方法，可以通过任何方式点击或者滚动都可以调用； ?ScrollBottom(function(){console.log(‘碰到底部：‘,123)}) ?//点击： $("jsMoreTip").click(function () { __morebook() }); ?????//滚动条到底部触发的事件 ?function ScrollBottom(x){ ???function __getScrollTop(){ ?　　 ???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; ?　　 ???return scrollTop; ???} ???function __getWindowHeight(){ ?　　 ???var windowHeight = 0; ?　　 ???if(document.compatMode == "CSS1Compat"){ ???????windowHeight = document.documentElement.clientHeight; ?　　 ???}else{ ?　　　　 ???windowHeight = document.body.clientHeight; ?　　 ???} ?　　 ???return windowHeight; ???} ???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; ?　　 ???return scrollHeight; ???} ???window.onscroll = function(){ ???????if(__getScrollTop() + __getWindowHeight() == __getScrollHeight()) ???????doFun(x) ???}; ?} ?function doFun(x){setTimeout(x,0)}