Ajax初体验--前台页面与后台的交互

<script language="javascript">  

function getKQSL(){
  var xmlHTTP = newXMLHttpRequest();//得到XMLHttpRequest对象
          var surl="XXX.do";  
  xmlHTTP.open("POST",surl, false);  
  xmlHTTP.send("");//发送请求
            if(xmlHTTP.readyState==4){  
      var retvalue=xmlHTTP.responseText;//得到返回值    
            }
  xmlHTTP=null;
  return retvalue;
}

function newXMLHttpRequest() {

  var xmlreq = false;

  if (window.XMLHttpRequest) {

    // Create XMLHttpRequest object in non-Microsoft browsers
    xmlreq = new XMLHttpRequest();

  } else if (window.ActiveXObject) {

    // Create XMLHttpRequest via MS ActiveX
    try {
      // 得到IE6.0+之后的XMLHttpRequest对象
      xmlreq = new ActiveXObject("Msxml2.XMLHTTP");

    } catch (e1) {

      // Failed to create required ActiveXObject

      try {
        // Try version supported by older versions
        // of Internet Explorer

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

      } catch (e2) {

        // Unable to create an XMLHttpRequest with ActiveX
      }
    }
  }

  return xmlreq;
}

</script>