Facebook is releasing the principles it uses to make sure the social network accessible to all users -- regardless of physical ability. The "accessibility toolkit," which the company will make public Tuesday, includes everything from how Facebook ensures that its engineers think about those issues to its strategies for building accessibility features into the site.

Different companies handle features for blind, deaf or otherwise disabled users in different ways. At Facebook, there's a whole team devoted to this idea: the Empathy Lab.

The name may sound a little squishy -- or disingenuous, depending on your level of cynicism. But it's a name that's been carefully chosen, said Ramya Sethuraman, an accessibility engineer who runs the lab.

"Accessibility tends to be a hard process for people [to understand]," said Sethuraman. "Calling it the Empathy Lab is better because everyone understands that concept."

Understanding and awareness, after all, are two of the biggest roadblocks to getting product engineers to think about issues of accessibility. Often, making the Web accessible comes as an afterthought -- not because companies are actively trying to keep anyone from using their products, but because they simply don't think about the issue until they receive feedback from users.

Facebook's Jeffrey Wieland, the manager of the accessibility engineering team, said that his goal is to help all the company's engineers think about the needs of disabled Facebook users from the start. The company works to build "core components" that were designed with accessibility in mind as the basic building blocks for every thing on the mobile and desktop site.

That ensures that these issues get addressed from the start, even at tech companies such as Facebook that famously want to move, test and tweak their products quickly.

"It's quite important for the strategy," Wieland said, of baking accessibility into the site from the start.

At the lab, engineers work on the site using, for example, a computer that doesn't have a mouse, to simulate the experience of a person who only has enough mobility to use a keyboard. (Pro-tip: Hitting "J" and "K" will let you scroll to the next or previous items on your News Feed.)

They also work on machines with screen readers, which are used by blind or visually impaired Web users to navigate pages, as well as with mobile devices with features such as Apple's VoiceOver or Android accessibility features enabled to make sure that everything on the network can be used by everyone.

And accessibility doesn't only mean dealing with physical disabilities -- it also means addressing technological ones. Sethuraman said that the Empathy Lab also looks at how to design Facebook for different parts of the world, where screens may be smaller and the Internet connections a little slower.

The company also works with several of its competitors and tech peers such as LinkedIn, Yahoo and eBay to talk over how they all work to make their sites easier to use. Every May on Global Accessibility Awareness Day, representatives from these and other companies meet for a sort of lightning TED-style talks to share their success and failures in tackling these issues.

"Our goal is to connect everyone in the world, and there ARE huge differences in the way that people interact with Facebook," Wieland said. "We want to build products that really work for everyone and can be used by everyone."