如何在Chrome应用中加入jQuery？

Question

I need access to some jQuery methods in my Chrome app, but am unsure how to include the API. I'm new to front-end development and am basically looking for some kind of .h #include parallel to what I normally do with more C-like languages.

In my manifest.json, I tried adding a path to a downloaded version of jQuery:

{
  "name": "my first app",
  "manifest_version": 2,
  "version": "0.0.1",
  "minimum_chrome_version": "36.0.1941.0",
  "app": {
    "background": {
      "scripts": [ "./assets/js/main.js",  "./assets/third-party/js/jquery-2.1.1.js"]
    }
  }
}

In my main.js file:

chrome.app.runtime.onLaunched.addListener(function() {
  chrome.app.window.create(
    "index.html",
    {
      innerBounds: {width: 800, height: 510, minWidth: 800}
    });
});

In my index.js, I don't have visibility to any width() method:

(function() {
  var ui = {
    update: null,
  };

  var initializeWindow = function() {
    console.log("Initializing window...");
    for (var k in ui) {
      var id = k.replace(/([A-Z])/, '-$1').toLowerCase();
      var element = document.getElementById(id);
      if (!element) {
        throw "Missing UI element: " + k;
      }
      ui[k] = element;
    }
    ui.update.addEventListener('click', onUpdateClicked);
    console.log("done initializing window");
  };

  var onUpdateClicked = function() {
    console.log("update button was clicked");
    updateProgressBar(0.25);
  };

  var updateProgressBar = function(percent) {
    var elem = document.getElementById("progressbar");
    console.log("Updating progress bar...");
    var progress_width = percent * elem.width() / 100;
    elem.find('div').animate({ width: progress_width }, 500).html(percent + "% ");
  };

  window.addEventListener('load', initializeWindow);
}());

jQuery width() method documentation

Answer 1

Scripts defined in the manifest only apply to background event page (where you probably don't need jQuery at all).

To use jQuery in index.html , you should reference a local copy of it in a <script> tag. Be careful to include it in the right order.

---

That said, there's a problem with your code.
You are mixing up DOM elements and jQuery "elements".

var elem = document.getElementById("progressbar");

returns a DOM element. You can convert it to a jQuery element with $(elem) , or query the jQuery way instead:

var elem = $("#progressbar");

Once you do that, you'll have access to jQuery methods.

PS I put "elements" in quotation marks because jQuery methods manipulate "sets of matched elements" instead. In this case, a single element matches an id query.

Answer 2

You need to add the path to the downloaded library in your html.

In index.html , just before your closing body tag:

    ...
      <!-- JavaScript -->
      <script src="assets/third-party/js/jquery-2.1.1.js"></script>
    </body>
    ...