<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <style> #div1 {100px; height:100px; background:red; position:absolute;} </style> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> <script> var iSpeedX=12; var iSpeedY=8; function startMove() { setInterval(function (){ var oDiv=document.getElementById('div1'); iSpeedY+=3; var l=oDiv.offsetLeft+iSpeedX; var t=oDiv.offsetTop+iSpeedY; if(t>=document.documentElement.clientHeight-oDiv.offsetHeight) { iSpeedY*=-0.8; iSpeedX*=0.8; t=document.documentElement.clientHeight-oDiv.offsetHeight; } else if(t<=0) { iSpeedY*=-1; iSpeedX*=0.8; t=0; } if(l>=document.documentElement.clientWidth-oDiv.offsetWidth) { iSpeedX*=-0.8; l=document.documentElement.clientWidth-oDiv.offsetWidth; } else if(l<=0) { iSpeedX*=-0.8; l=0; } if(Math.abs(iSpeedX)<1) { iSpeedX=0; } if(Math.abs(iSpeedY)<1) { iSpeedY=0; } oDiv.style.left=l+'px'; oDiv.style.top=t+'px'; document.title=iSpeedX; }, 30); } </script> </head> <body> <input type="button" value="开始运动" onclick="startMove()" /> <div id="div1"> </div> </body> </html>