Web standards-availability, maintainability, and accessibility

In the Web Front-end development field, three words are often mentioned: availability, accessibility, and maintainability ).

Availability refers to whether the product is easy to use, whether the user can complete the task, how efficient the product is, and whether the user's subjective feelings are good during the process. The quality of the product is determined from the user's perspective. Good availability means high product quality and is the core competitiveness of enterprises.

Maintainability generally includes two levels. One is the cost of quickly locating and solving problems when the system encounters problems, and the maintainability is good if the cost is low. SecondCodeWhether it is easy to understand, whether it is easy to modify and enhance functions. Maintainability, reusability, scalability, and so on. Building codes with good maintainability is very important for the long-term development of enterprises.

The definition of availability and maintainability is clear, and there are a lot of research in the software field. We will not discuss it here. Let's look at the accessibility.

What is accessibility? It is difficult to give a strict definition. In Web Content Accessibility Guidelines 1.0 (Web Content Accessibility Guide), accessibility is described as: the readability and comprehensibility of web content for users with disabilities. At the same time, it is also pointed out in the guide that improving accessibility can also make it easier for common users to understand web content. Specifically, you must consider the following two aspects:

1. Whether the user is physically impaired or not, the user agent must be used to access the Web content. Therefore, to improve accessibility, you must first consider a variety of user agents: desktop browsers, voice browsers, mobile phones, and on-board PCs. At Google, employees with disabilities were hired to help improve product accessibility.
2. You must also consider the environment restrictions when users access web content. For example: Noisy Environments, rooms that are too dark or too bright, or hands-free. This is a higher level of accessibility requirements. By doing so, the core competitiveness of products in specific fields can be created.

Understanding the above two points can answer a lot of questions. For example, web developmentCommunityFrequently discussed topics: do we really need to consider Disabling JavaScript/CSS in browsers? In my understanding, the consideration is not to disable javascript/CSS browsers, but to user proxies that do not support or do not support JavaScript/CSS well. For example, voice reader and mobile browser, JavaScript provides a layer of accessibility and cannot replace the content itself. Of course, from the perspective of progressive enhancement, we encourage the use of advanced features, but at the same time, we must achieve an elegant degradation so that low-end user agents can also retain the real experience of subsistence allowances.

Understanding the accessibility and help you better understand the importance of semantics. Why is the difference between EM and strong important? Because the two tags are different in the speech reader, incorrect use may lead to incorrect tone changes and incorrect accent positions. This is a huge disrespect for blind users.

Focusing on accessibility is a kind of respect for the elderly and children on the Internet. It reflects the morality and care of front-end development engineers for society.