Ajax解析XML

Question

I have a loginmein.aspx page with two textboxes and a button. I am calling a web service called verify.aspx, that if the login is correct, it returns hello! in xml format(below).

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<response>
    <command method="alert">
        <message>hello world!</message>
    </command>
</response>

I have built another simple application to learn how to call the same web service via ajax.

How do I read "hello !" and display true or false by ajax to a label on a browser?

Answer 1

You can parse the XML response using DOMParser:

var xmlhttp = new XMLHttpRequest();

xmlhttp.onreadystatechange = function () {
    if (xmlhttp.readyState === 4 && xmlhttp.status === 200) {
        var resXml = xmlhttp.responseText;
        document.getElementById("lblMessage").innerHTML = resXml;

        var parser = new DOMParser(),
            doc = parser.parseFromString(resXml, 'text/xml'),
            message = doc.querySelector('response > command > message');

        // check for existence of 'message' element
        if (message != null)
            alert(message.textContent); // hello world!
        else
            alert('Oops!'); // error
    }
};

xmlhttp.open("GET", "microsoft/webservice/verify.aspx?username= " + document.getElementById("txtUserName").value + "&password=" + document.getElementById("txtPassword").value, true);
xmlhttp.send();

See DomParser