js Date自定义函数 延迟脚本执行

function delay(numberMillis){ 
var now = new Date(); 
var exitTime = now.getTime()+numberMillis; 
while(true){ 
now = new Date(); 
if(now.getTime() > exitTime) 
return; 
} 
} 
document.write("<script language='javascript' src='js1.js'></script>");