<!DOCTYPE html> <html> <head> <meta http-equiv="content-type" content="text/html; charset=gb2312"/> <title>js </title> </head> <body> <script type="text/javascript"> function getcl(){ var arr = [] i =0; C = '0123456789ABCDEF'; while(i++ < 6){ x=Math.random()*16; b=parseInt(x); c=C.substr(b,1); arr.push(c); } var cl = "#"+ arr.join(''); return cl; } document.write(cl); function setColor(){ document.getElementById("myDiv").style.backgroundColor = getcl(); } </script> <div id="myDiv" style="200px;height:200px;"></div> <input type="button" value="myDiv" onclick="setColor()" /> </body> </html>