MDNJump

MDNJump is a simple extension for Google Chrome which adds a context menu for text selections allowing quick reference lookups on the fly. MDNJump also adds an Omnibox keyword mdn- which you can use in Chrome's address bar. MDN is generally my favorite reference for front-end development. I created this extension so I could more quickly search it's documentation.

Usage

To use MDNJump, select some text on a page you're reading such as window.location and right click. The MDNJump context menu entry will be present. Click the menu button and instead of being brought to a search results page, you will jump directly to this wonderful reference.

You may also use MDNJump through Chrome's Omnibox (the address bar). Simply type mdn- and hit TAB or SPACE to activate MDNJump. You may then enter a query and jump directly to the top MDN page for that given query.

Permissions

• Tabs -- MDNJump will open a new tab when you perform a jump.
• Context Menus -- MDNJump will create a context menu item for use when the context menu is activated while text is selected.

Technical

When I set out to create this extension I first looked at how I could dynamically query MDN based on a text selection. I began by trying to construct a URL which would take the following form:

http://developer.mozilla.org/search?q=Your+text+selection+here

This allows me to construct a URL based on a text-selection to query MDN, however, it's kind of a pain to have to select the top entry on the MDN search results page every time. I could find no way to simply link directly to the top search result. What I needed was something like the [I'm Feeling Lucky][lucky-button] on Google's search page. This would allow me to jump directly to the top result.

This gave me an idea: why not simply use the I'm Feeling Lucky feature from Google? I began looking around to see if it was possible to construct a Google search query URL which allowed use of the Feeling Lucky feature. I found this [Stack Exchange question][lucky-blog-post] which explained that adding the field btnI in the query string would enable I'm Feeling Lucky.

So we can use URLs of the following form:

http://google.com/search?btnI&q=Your+text+selection+here

I created a simple function used to construct these URLs, optionally restricting them to a given domain:

/** Constructs a URL which will query google redirecting to the top
    query result (optionally restricted to a particular domain) */
var getLucky = function (query, site) {
	site = site ? ['site:', site, '+'].join('') : '';
	return ['https://google.com/search?btnI&q=', site, query].join('');
};

Using this I am able to get the URLs of the following form, which is what MDNJump opens in a new tab based on your text selection:

http://google.com/search?btnI&q=site:developer.mozilla.org+Your+text+selection+here