<script type="text/javascript"> //var timer=null;?window.onscroll=function(){ var scrollT=document.documentElement.scrollTop||document.body.scrollTop; var top=scrollT+(document.documentElement.clientHeight-$("box").offsetHeight)/2; showmove(top);}function showmove(target){ var timer=null; clearInterval(timer); timer=setInterval(function(){ var timer=null; var speed=(target-$("box").offsetTop)/8; speed=speed>0?Math.ceil(speed):Math.floor(speed); if ($("box").offsetTop==target) { clearInterval(timer); }else{ $("box").style.top=$("box").offsetTop+speed+"px"; document.title=speed; $("box1").style.top=$("box").offsetTop+speed+"px"; } },100)}function $(id){ return document.getElementById(id);}</script>
timer=null;為什么要作為全局變量。如果聲明timer=null;為局部變量,就會出問題,一直沒搞懂
carey2015
2016-01-16 13:15:40