var xmlHttp;
function createXMLHttpRequest(){
  if(window.ActiveXObject){
         xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
  }
  else if(window.XMLHttpRequest){
         xmlHttp = new XMLHttpRequest();
  }
}
function logout(){
    createXMLHttpRequest();
    var url = "/user/logout.asp"
    xmlHttp.open("get",url,true);
    xmlHttp.onReadyStateChange = function(){
   if(xmlHttp.readyState == 4)
    {
        if(xmlHttp.status == 200)
        {
          var dates = xmlHttp.responseText;
          window.document.forms[0].innerHTML=dates;
        }
    }else
    	{
         window.document.forms[0].innerHTML="正在加载数据,请稍等";
    	}
	};
    xmlHttp.send(null);
}
function ajaxSubmit()
{
    createXMLHttpRequest();
    var username = window.document.forms[0].username.value;
	var password = window.document.forms[0].password.value;
	if(username==''){
		window.alert('请输入用户名!');
		window.document.forms[0].username.focus();
		return false;
		}
	if(password==''){
		window.alert('请输入密码!');
		window.document.forms[0].password.focus();
		return false;
		}
    var url = "/user/checklogin.asp";
    var postdate = "username="+username+"&password="+password;
    //window.alert(postdate);
	xmlHttp.open("post",url,true);
    xmlHttp.setRequestHeader("content-length",postdate.length);//post提交设置项
    xmlHttp.setRequestHeader("content-type","application/x-www-form-urlencoded");//post提交设置项
    xmlHttp.onReadyStateChange = function(){
    if(xmlHttp.readyState == 4)
    {
        if(xmlHttp.status == 200)
        {
          var dates = xmlHttp.responseText;
          window.document.forms[0].innerHTML=dates;
        }
    }else
    	{
         window.document.forms[0].innerHTML="正在加载数据,请稍等";
    	}
	}
    xmlHttp.send(postdate);}

function relogin(){
var getstr='用户名：<input type="text" name="username" value="" size=14 maxlength=16/>&nbsp;密码：<input type="password" name="password" size=14 maxlength=16/>&nbsp;<input type="submit" name="button" value="" class="button" onClick="ajaxSubmit()">&nbsp;&nbsp;&nbsp;&nbsp;<a href="/user/register.asp" class="red">免费注册</a>&nbsp;&nbsp;<a href="#" class="red">忘记密码？</a>';
document.forms[0].innerHTML=getstr;
}
function CheckUsername(username){
	if(username==''){window.alert('请输入用户名');return false;}
	createXMLHttpRequest();
	var url = "checkusername.asp?username="+username;
	xmlHttp.open("get",url,true);
	xmlHttp.send(null);
	xmlHttp.onReadyStateChange=function(){	
	if(xmlHttp.readyState == 4)
    {
        if(xmlHttp.status == 200)
        {
          var dates = xmlHttp.responseText;
          window.alert(dates);
        }
    }
	}
}