JavaScript实现WebService的http的Post请求

//*******************************javascript 这个脚本实现Webservice调用******************************************//

function AjaxFunc()
{
var url="http://localhost/MyService/Service.asmx"; 
var method="DollarConvertToRMB";
var params="Dollar";
var paramsValue="1";
var xmlhttp;

  if(window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
  else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }

  xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
     document.getElementById

("nameText").innerText=xmlhttp.responseText;
    }
  }
 
  xmlhttp.open("POST",url+"/"+method,true);
  xmlhttp.setRequestHeader("Content-Type", "application/x-www-

form-urlencoded");
  xmlhttp.send(params+"="+paramsValue);
 

}

//********************************Webservice后台代码部分**********************************//

 [WebMethod]
    public double DollarConvertToRMB(double Dollar) {
        return (Dollar * 8.15);
    }