function getXHR() 
{
var xhr;
 try
    {
   // Firefox, Opera 8.0+, Safari
    xhr=new XMLHttpRequest();
    }
 catch (e)
    {
  // Internet Explorer
   try
      {
      xhr=new ActiveXObject("Msxml2.XMLHTTP");
      }
   catch (e)
      {

      try
         {
         xhr=new ActiveXObject("Microsoft.XMLHTTP");
         }
      catch (e)
         {
         alert("您的浏览器不支持AJAX！");
         return null;
         }
      }
} 
if(!xhr&&typeof XMLHttpRequest!='undefined') 
{
xhr=new XMLHttpRequest();
}
return xhr;
}
function openXHR(method,url,callback) {
var xhr=getXHR();
xhr.open(method,url);
xhr.onreadystatechange=function() {
if(xhr.readyState!=4)return;
callback(xhr);
}
xhr.send(null);
}
function loadXML(method,url,callback) {
var xhr=getXHR();
xhr.open(method,url);
xhr.setRequestHeader("Content-Type","text/xml");
xhr.setRequestHeader("Content-Type","GBK");
xhr.onreadystatechange=function() {
if(xhr.readyState!=4)return;
callback(xhr);
}
xhr.send(null);
}
function $(selector)
{
return document.getElementById(selector);
}

//var beg=window.location.search.indexOf('=');
//var room =window.location.search.substring(beg+1);
//document.write("<script type='text/javascript' src='../js/seeit.js'></script>");
//响应回车
document.onkeydown = function(event)
{   
	var eve = event || window.event; 
    if(eve.keyCode == 13)
    {
       document.getElementById("btnSend").focus();
    }
}
function queryString(sFieldName, isAutoDecodeURI) 
{
//获取查询字符串中的指定字段的值.
    var r, r = (r = window.location.search.substr(1).match(new RegExp("(^|&)" + sFieldName + "=([^&]*)(&|$)"))) ? r[2] : null;
    return r != null ? isAutoDecodeURI ? decodeURI(r) : r : null;
}