function CheckNewMessage(){ var Url = "http://message.csdn.net/newMessage.aspx "; var nn = Math.floor( Math.random() * 2000000); Url += "?time= "+nn; var ScriptName = "CheckUserHasNewMessage "; var head= document.getElementsByTagName( "head ").item(0); var old = document.getElementById(ScriptName); if (old) head.removeChild(old);
//--> </script> </body> </html> ----------------- 1、其中有两个函数不太明白,一个是CheckNewMessage(),从名称上看应该是检查是否有新消息,但这段代码: var ScriptName = "CheckUserHasNewMessage "; var head= document.getElementsByTagName( "head ").item(0); var old = document.getElementById(ScriptName); if (old) head.removeChild(old);