idkt
2015-08-12 00:34:22
window.onload=function(){ var xin=document.getElementById('xin'); var speed=2; document.getElementById('dongzuo').onclick=function(){ speed+=5; setInterval(function(){ var old_top=xin.offsetTop; var new_top=old_top+speed; var old_left=xin.offsetLeft; var new_left=old_left+5; if(new_top>=365){ new_top=365; speed *= -0.8; } if(new_top<=0){ new_top=0; speed *= -0.8; } xin.style.top=new_top+'px'; xin.style.left=new_left+'px'; },10) } }
6 回答

王醒醒ok
TA貢獻(xiàn)5條經(jīng)驗(yàn) 獲得超1個(gè)贊
speed*=-0.8, 計(jì)算奇數(shù)次,speed為負(fù),偶數(shù)次speed又為正,怎么能不斷減速呢?!
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