regist.js

jsp+servlet网上购物,是一个实现mvc的网站

var xmlHttp;
function creatXmlHttp() 
{
        if (window.XMLHttpRequest) 
      {
           xmlHttp = new XMLHttpRequest();                 
        }
   else {
           xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
         }
        return xmlHttp;
}
function beginCheck()
   {
         var username=document.all.username.value;
         creatXmlHttp();
         xmlHttp.onreadystatechange=processor;
         open("get","checkUser?name="+username);
         send(null);        
    }
function processor()
 {
       var responseContext;
       if(xmlHttp.readyStates==4)
        {
               if(xmlHttp.status==200)
                 {
                      responseContext=xmlHttp.reponseText;
                     if( responseContext.indexOf("true")==-1)
                               {
                                 alert("恭喜你，用户名可用");
                                }
                         else
                               {
                                 alert("对不起，用户名已被注册");
                                }
                 }
   
       }
}