如何使用用户名和密码发出Http请求

我试图向一个网站提出Http请求，假设是gmail.com。一旦gmail打开，需要提供用户名，密码。然后我需要获取数据并在我的应用程序中使用它。我能用Java做，但我的项目在MFC中，我使用DHtmalDialog来使用javascript。这是我现在编写的代码。请帮帮我，我是javascript的新手。



//这里调用函数

httpGet（gmail.com）; // gmail就是例如

Hi,

I am trying to make Http request to one site suppose "gmail.com". Once gmail opens need to provide username ,password. then I need to get data and use it in my application. I am able to do it in Java, but my project is in MFC and I am using DHtmalDialog to use javascript. here is my code what I have wrote upto now. Please help me I am new in javascript.

// Here calling the function
httpGet("gmail.com"); // gmail is just for example

function httpGet(theUrl)
       {
           var xmlHttp = null;
           xmlHttp = new XMLHttpRequest();
           xmlHttp.open("POST", theUrl, false);
           xmlHttp.setRequestHeader("username", "invalid");
           xmlHttp.setRequestHeader("password", "invalid;);
           xmlHttp.setRequestHeader("Content-Type", "application/json");
           xmlHttp.setRequestHeader("Accept", "application/json");
           xmlHttp.setRequestHeader("Accept-Encoding", "gzip,deflate");
           xmlHttp.send();
           alert(xmlHttp.readyState); // here I am getting 4
           alert(xmlHttp.status); // here I am getting 200
           alert(xmlHttp.responseText); // but here it is blank
          // xmlHttp.responseType = "json";

           if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
               alert(xmlHttp.responseText); // here also it is blank
               }
           else {
               alert("fail to get status");
           }
           return xmlHttp.responseText;
        }