tempid = new Array();   
tempid[0] = "<script language=javascript src='调用'><"+"/SCRIPT>"  
tempid[1] = "<script language=javascript src='调用'><"+"/SCRIPT>"  
tempid[2] = "<script language=javascript src='调用'><"+"/SCRIPT>"  

showId = Math.floor(Math.random() * 3);   
document.write(""+tempid[showId]+"");