//定义全局的xml对象
var xmlHttp = null;
function GetXmlHttpObject()
{
var xmlHttp=null;
try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
    }
catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    }
if(xmlHttp == null)
alert("对不起,您的浏览器不支持Ajax");
return xmlHttp;
}

function sendGetAction(url,myStateChanged){
//get传送

if (xmlHttp==null)
{
   xmlHttp=GetXmlHttpObject();

}

//指定响应函数
xmlHttp.onreadystatechange=myStateChanged;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}

function getQuery(form){
//将表单元数拼成Query条件
    queryString="";
   

    var numberElements = form.elements.length;
    for(var i = 0; i < numberElements; i++) {
        if(i < numberElements-1) {
            queryString += form.elements[i].name+"="+
                           encodeURI(encodeURI(form.elements[i].value))+"&";
        } else {
            queryString += form.elements[i].name+"="+
                           encodeURI(encodeURI(form.elements[i].value));
        }

    }
return queryString;
   
}

function sendGetForm(form,myStateChanged){
//表单GET提交
var queryString = getQuery(form);
var url = form.action;
url = url+"?"+queryString+"&sid="+Math.random();
sendGetAction(url,myStateChanged);

}

function sendPostAction(url,strQuery,myStateChanged){
//post传送

   if (xmlHttp==null)
{
xmlHttp=GetXmlHttpObject();

}
xmlHttp.open("POST",url,true);
xmlHttp.onreadystatechange=myStateChanged;
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
xmlHttp.send(strQuery);//发送请求
};

function sendPostForm(form,myStateChanged){
//表单post提交
var queryString = getQuery(form);
var url = form.action;
sendPostAction(url,queryString,myStateChanged);

}