CODEWITHSUNDEEP
javascriptgoogle-chromegoogle-chrome-extensionxmlhttprequest
MercuryMan
MercuryMan

Reputation: 173

XMLHttpRequest status 0 in click event handler

I'm writing a Google Chrome extension to take advantage of an API we have written. The problem I'm having is that the popup.html has a login form, and when the submit button is pressed it calls the necessary authentication code, which involves making a couple of XMLHttpRequests to the API server.

The code is as follows:

authenticate.js

function authenticate(username, password)
{
  var xhr = new XMLHttpRequest();
  xhr.open("GET", "<api-server>/challenge?username=dummyusername", true);
  xhr.onreadystatechange = function() {
    if (xhr.readyState == 4) {
      alert(xhr.status);
    }
  };
  xhr.send();
}

/*Gets the username and password textboxes from popup.html and passes their values on to authenticate()*/
function getCredentials()
{
  authenticate("test", "test");
}

document.addEventListener("DOMContentLoaded", function() {
  var submitBtn = document.getElementById("submitBtn");
  if (submitBtn != null) {
    submitBtn.onclick = getCredentials;
  }
});

popup.html

<!doctype html>
<html>
  <head>
    <title>Login Page</title>
  </head>
  <body>
  <form>
    <label for="username">Username:</label>
    <input type="text" id="usernameTxt"><br>
    <label for="password">Password:</label>
    <input type="password" id="passwordTxt"><br><br>
    <input type="submit" id="submitBtn" value="Submit">
  </form>
  <script src="authenticate.js"></script>
  </body>
</html>

manifest.json

{
  "manifest_version": 2,

  "name": "Chrome Extension",
  "description": "Chrome Extension",
  "version": "1.0",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "<all_urls>",
    "activeTab",
    "https://ajax.googleapis.com/",
    "<api-server>"
  ]
}

If, however, I replace:

document.addEventListener("DOMContentLoaded", function() {
  var submitBtn = document.getElementById("submitBtn");
  if (submitBtn != null) {
    submitBtn.onclick = getCredentials;
  }
});

with:

document.addEventListener('DOMContentLoaded', function() {
  getCredentials();
});

it does the right thing, which leads me to believe it's to do with the fact that it's being called from a click event handler and perhaps somehow the permissions haven't been extended to the button.

I saw this post (Chrome Extension: XMLHttpRequest canceled (status == 0)) and added "<all_urls>" to permissions and that has made no difference.

Upvotes: 0

Views: 97

Answers (1)

epascarello
epascarello

Reputation: 207501

Cancel the click so the form does not submit.

document.getElementById("submitBtn").addEventListener('click', function(evt){
    evt.preventDefault();
    getCredentials();
});

Upvotes: 2

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