Get JSON from Web Service Using JavaScript

Question

I get this error when I click the button in HTML to use my JavaScript.

myapp.azurewebsites.net/:1 Uncaught SyntaxError: Unexpected end of JSON input
 at JSON.parse (<anonymous>)

JS:

function ajaxFunction() {
 console.log("ajaxFunction()");
 var ajaxRequest;
 try {
 ajaxRequest = new XMLHttpRequest();
 } catch(e) {
 try {
 ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
 } catch(e) {
 try {
 ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
 } catch(e) {
 alert("Broken");
 return false;
 }
 }
 }
 ajaxRequest.onreadystatechange = function () {
 if (ajaxRequest.readyState == 4 && ajaxRequest.status == 200) {
 var form = document.getElementById("myform");
 var titleParagraph = document.getElementById("home_title");
 titleParagraph.innerHTML = ajaxRequest.responseText;
 form.style.display = "none";
 }
 } 
 var value1 = document.getElementById("field1").value;
 var value2 = document.getElementById("field2").value;
 var url = "https://webapp.azurewebsites.net/users/" + value1 + "/" + value2;
 console.log(url);
 // Call sign in web service
 ajaxRequest.open("GET", url, true);
 ajaxRequest.send(null);
 var jsonResponse = JSON.parse(ajaxRequest.responseText);
 console.log("RESPONSE:");
 console.log(jsonResponse);
}

This JSON is what I get when I go to https://webapp.azurewebsites.net/users/value1/value2

[{"ID":1,"UserName":"username","FirstName":"first","LastName":"last","email":"[email protected]"}]

• Jordan Running: What is the actual value of ajaxRequest.responseText?
• raginggoat: @JordanRunning see my update.
• maioman: try checking for ajaxRequest.responseText in the readystatechange handler you set up (inside readyState == 4 && status == 200 block)

Answer 1

ajaxRequest.open("GET", url, false);

Third parameter says if the request is asynchronous or not. So by looking at your code it should be synchronous.

• raginggoat: When I change that, I get No 'Access-Control-Allow-Origin' header is present on the requested resource
• Volem: Use setRequestHeader() to add that into it