Ajax实现局部刷新

Ajax实现局部刷新

    <script type="text/javascript">

    var xmlhttp;

    function getData()

    {

      //获取用户填写的名称

      var city=document.getElementByIdx("txt").value;

      //创建异步调用对象

      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");

      //将对象状态与事件相关联

      xmlhttp.onreadystatechange=statechange;

      //加载要链接的页面

      xmlhttp.Open("POST","datapage.aspx?city=" +city,true);

      //发送请求

      xmlhttp.Send();

    }

    function statechange()

    {

      //判断异步调用是否已经完成

      if(xmlhttp.readystate==4)

      {

        //判断完成的提示代码是否是OK状态

        if(xmlhttp.status==200)

        {

           //将返回数据作为参数，传递给填充方法

           FillData(xmlhttp.responseText);

        }

      }

    }

    function FillData(strcity)

    {

       document.getElementByIdx("DropDownList1").options.length=0;

       var indexofcity;

       var city;

       //切割传递来的字符串

       while(strcity.length>0)

       {

       //判断是否是最后一个字符串

        indexofcity=strcity.indexOf(",");

        if(indexofcity >0)

        {

        city=strcity.substring(0,indexofcity);

        strcity=strcity.substring(indexofcity+1);

        //填充下拉框

        document.getElementByIdx("DropDownList1").add(new Option(city,city));

        }