Focus Management

Definition

The practice of programmatically controlling where the keyboard focus is on a webpage using JavaScript, usually in response to dynamic UI changes like opening a modal or loading a new page.

Explain Like I'm New

When you click a button to open a popup Modal, a keyboard user expects their 'Tab' key to immediately start tabbing through the Modal. If you don't use JavaScript to physically move their focus into the Modal, they will be stuck tabbing through the hidden background page behind the Modal.

Real World Example

Creating a 'Skip to Main Content' link at the very top of a page. Keyboard users press enter, and JavaScript instantly moves their focus past the 20 navigation links straight to the article.

Common Use Cases

•Modals and Dialogs
•Single Page Applications (React/Next.js routing)
•Skip links

Interactive Example

Interview Questions

basic

What JavaScript method is used to force focus onto an element?

intermediate

What is a 'Focus Trap'?

Flash Cards

Question

What method?

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Answer

`element.focus()`

Question

What is a Focus Trap?

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Answer

When a Modal is open, the user should not be able to tab OUT of the Modal. A focus trap is a JavaScript script that listens for the Tab key. When the user reaches the last button in the Modal and presses Tab, it forces the focus back to the first button in the Modal, 'trapping' them safely inside.