Page performance is always something we should consider when building websites and applications, whether that's real or the way that a user perceves your site is loading. Some experts would actually say that in some situations, perception of load times is more important than actual load times; it's why some people prefer progress bars over spinners.
If you're developing for the front end, then it's important to understand how to test that what you produce is accessible. Testing across multiple browsers has been part of front end development since the beginning; browsers would always interpret your code in slightly different ways, both small and large. Accessibility testing is no different really, you're just approaching things from a slightly…
With more and more web usage being performed on mobile devices, increasing every year the, now common, hamburger menu is here to stay. One of the main problems that needs addressing is the usability and accessibility of the menu.
A Typical Example
Improving for the Screen Reader
Setting the Expanded State