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检测滚动条是否滚动到底部：
<body><div id="outerctn"><div id="innerctn"><div id="innerctn1">测试div1</div><div id="innerctn2">测试div2</div><div></div></body><script type="text/javascript">var $outerctn=$('#outerctn');var innerctn=$('#innerctn');var scrollHeight=$outerctn.scrollHeight;var $outerctn_h=$outerctn.height();var innerctn_h=innerctn.height();var scrollTop=innerctn_h-$outerctn_h;$outerctn.on('scroll',function(){console.log($(this).scrollTop(),scrollTop)if($(this).scrollTop()>=scrollTop){console.log('滚动条到达底部了')}})</script>
