Link Hints

What is Link Hints?

Link Hints is a browser extension that complements the built-in keyboard shortcuts with ones for clicking.

Press AltJ. This makes little yellow boxes with letters, called hints, appear next to links (and other clickable things). Type the letters to click the link. Alternatively, hold Shift and type a bit of the link text.

There are a few variations on the above shortcut for opening links in new tabs or selecting text.

The keyboard shortcuts and hints are fully customizable.

What is Link Hints not?

Here are some features that Link Hints won’t implement.

• Vim-like or single-key keyboard shortcuts.
• Custom actions.
• Scrolling.
• Always-shown hints.

I’d like to focus on link hinting and do it really well. That’s complicated enough.

I’m interested in making Link Hints work together with Vim plugins, though.

How is Link Hints different?

Using hints to click links is not at all a new idea. What does Link Hints bring to the table?

Link Hints keeps track of all clickable elements in the background when your browser is idle. This makes hints appear quickly regardless of page size.

Other than accurately finding clickable elements, Link Hints also focuses on placing the hints intuitively and being generally easy to use and configure.

For the technically interested, here’s a list of fancy things:

• Full Shadow DOM support, including “closed” shadow roots.
• Seamless iframe support.
• Detection of covered elements using elementFromPoint.
• Background tracking of visible elements using MutationObserver, IntersectionObserver and requestIdleCallback.
• Tracking of elements with click listeners.
• Tracking of scrollable elements in Firefox.
• Tracking elements and updating hints while showing them.
• Text based hint positioning.
• Hint generation using weighted Huffman coding.
• Links with the same URL get the same hint.
• Elaborate workarounds for Firefox’s overzealous popup blocker and CSP rules.
• Support for different keyboard layouts.

Where can I see all keyboard shortcuts?

There isn’t that much to know besides the six shortcuts shown near the top of this page, really. Those are the main ones. But there are a few more shortcuts that you can learn as you need them.

Click the Link Hints toolbar button and then “Options.” There you’ll find an overview of all shortcuts (and you can change them there as well).

You’ll find explanations of the shortcuts in the tutorial.

What permissions does Link Hints need?

Browser extensions ask for permission to certain features when installed. This is to prevent extensions from silently stealing all your browsing data behind your back.

These are the permissions Link Hints needs:

• Access your data for all websites: The whole point of Link Hints is to run on all websites, monitor them for links and let you click them. Link Hints never sends any data anywhere.
• Storage: Link Hints needs to be able to save your options. (This one might not appear in the installation UI, but most extensions use it.)

Why doesn’t Link Hints work on some pages?

Browser extensions are not allowed to run on some pages, such as Chrome’s and Firefox’s extension stores, the New Tab page and internal settings pages.

The Link Hints toolbar button is faded out to indicate this. Regular look: . Faded: .

Other possible reasons include:

• The web page area is not focused. The Link Hints shortcuts only work when the web page area is focused, not when the address bar or the dev tools or any other part of the browser has focus. To move focus back to the page, either click somewhere on the page with the mouse, or press F6 one or two times. This isn’t ideal, but part of the limitations of browser extensions.
• The site is using some fancy technique that Link Hints does not support yet, or there’s a bug in Link Hints. Please report an issue!

What is the story behind Link Hints?

In 2013 I (Simon Lydell) started contributing to the VimFx browser extension, making significant work on its link hinting feature. After a while, I became the main developer.

When VimFx was discontinued in 2017 (due to Firefox dropping their old extension system in favor of cross-browser Web Extensions), I started thinking about making a new extension, porting my favorite feature of VimFx – link hinting.

During experimentation in early 2018, I discovered a way of keeping track of clickable elements in the background (for the technically interested, a combination of MutationObserver, IntersectionObserver and requestIdleCallback). This showed potential for greatly improving on the VimFx link hinting.

A couple of months later, the first commit of Link Hints was made (then called “Synth”). Soon it was stable enough to be used for day-to-day browsing. After almost two years of experimentation, development and real-world usage, Link Hints was first released in February 2020.