MDNJump is my first Chrome extension. The Mozilla Developer Network (MDN) is generally my favorite reference for front-end devleopment so I created MDNJump in order to more easily reference the source for documentation. MDNJump was also an excuse to quickly learn about Chrome extensions and it is available on GitHub at CoryG89/MDNJump. It was only a few days ago I started reading through some of the documentation for the different Chrome APIs for extensions, but I've already have envisioned and implemented an extension that is useful for my in-browser workflow. This is partly because Google has made it so extending Chrome is not much harder than doing basic web development with HTML markup and JavaScript. Accessing the Chrome APIs is just like working with any other JavaScript API. It's absolutely great. They also have good documentation available. I wrote a quick overview guide for creating extensions, recording what I've learned. It covers many of the major architectural aspects of extensions and goes over most useful and most commonly used APIs available.

Usage and Interface

MDNJump extends Chrome in two ways:

  • Omnibox keyword - Chrome's address/search bar is called the Omnibox. By default, the registered keyword for MDNJump is mdn- which, when entered in the omnibox, followed by either the TAB or SPACE key, activates MDNJump in the Omnibox. After MDNJump has been activated you may enter a query and when you press enter you will jump directly to the best MDN reference documentation for that query.

  • Context Menu - MDNJump also adds an entry to the right-click context menu when the menu is activated on a text selection. Highlight some text on a page such as window.location or string and jump directly to great documentation.

What Makes It So Special?

Nothing really. However, I don't know of a faster way to look something up on MDN and that was the goal. If you search the Chrome Webstore for MDN the only other extension you get is MDNSearch. Like MDNJump it registers an omnibox keyword, but when used it brings you to a search results page instead of directly to what you were looking for.

What Does MDNJump Do Different?

I was dissatisifed with extensions such as MDNSearch mentioned above. It's a good extension that does what it sets out to, but I wanted to jump directly to the top reference for my particular query. If you give MDNSearch the query window.location it will load the following search URL:

On the otherhand, instead of loading the search results page, MDNJump will send you directly to the top documentation for that query instead:

How Does It Work?

MDNJump works by leveraging Google's Search API and it's I'm Feeling Lucky feature. Instead of using the Mozilla URL, we instead use a Google Search URL with the btnI field specified:

The above URL pattern will perform a Google Search for query %s, restricted to the given domain Because the btnI field is specified, it will activate I'm Feeling Lucky and automatically redirect us to the top result.

MDNJump uses this technique in order to jump directly to the best MDN reference for your queries.

/** Google query URL with btnI key activates I'm Feeling Lucky */
var googleUrl = '';
var mdnUrl = '';

/** Returns a Google query URL using I'm Feeling Lucky given an unformatted
    query and optional domain string to restict the search to */
function getLucky (query, site) {
    site = site ? ['site:', site, '+'].join('') : '';
    return [googleUrl, site, query].join('');

chrome.omnibox.onInputEntered.addListener(function (query) {
    var luckyUrl = getLucky(query, mdnUrl);
    chrome.tabs.update({ url: luckyUrl });

blog comments powered by Disqus