ajax在FireFox浏览器中无法取值

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

Ajax Demo
function login() { var xmlHttp = false; try{ xmlHttp=new XMLHttpRequest();// Firefox, Opera 8.0+, Safari }catch (e){ //Internet Explorer try{ xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); }catch (e){ try{ xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); }catch (e){ alert("111"); return false; } } } var name = document.getElementById("myname"); var myname = name.getAttribute("value"); var password = document.getElementById("mypassword"); var mypassword = password.getAttribute("value"); //var serverUrl ="AjaxServlet"; var requestMethod = "GET"; //httpRequest= new ActiveXObject("Msxml2.XMLHTTP"); xmlHttp.onreadystatechange=function() { if(xmlHttp.readyState==4) { document.getElementById("info").innerHTML=xmlHttp.responseText; } } xmlHttp.open(requestMethod,"ajax/Ajax.jsp?name="+myname+"&password="+mypassword,true); xmlHttp.send(null); }

  <br><label id="info">
   UserName: <input type="text" name="name" id="myname"></input>
   PassWord: <input type="password" name="password" id="mypassword"></input>
  <input type="button" name="loginsub" value="Login" onclick="login();"></input>&#26410;&#30331;&#38470;</label>

整张代码在IE上面可以获取接收到的 username和password 但是在FireFox里面接收就为null 为什么

把那个参数name和password改成var name=document.getElementById("myname").value,密码同上。试试

[quote] function login()
{
var xmlHttp = false;
try{
xmlHttp=new XMLHttpRequest();// Firefox, Opera 8.0+, Safari
}catch (e){
//Internet Explorer
try{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}catch (e){
try{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}catch (e){
alert("111");
return false;
}
}
} [/quote]

为什么给xmlHttp赋值了3次？最好判断什么样的浏览器赋什么样的值

var xmlHttp;