Category: JavaScript

Create a tab interface that updates panels reliably and supports the ARIA roles, selected state, roving tabindex, and arrow-key behavior users expect.

Count repeated values with a JavaScript Map, keep the result reusable, and convert it to a plain object only when an API or JSON output requires one.

Use DevTools call stacks, source maps, script URLs, and extension isolation to identify whether a JavaScript error comes from your code or injected code.

Create a client-side text or CSV download with Blob, an object URL, the download attribute, UTF-8 handling, and timely URL cleanup.

Resize a selected browser image with createImageBitmap and canvas, preserve aspect ratio, export a Blob, and upload the smaller file.

Disable a form’s submit controls after a valid submission, show progress, handle failed asynchronous requests, and still enforce idempotency on the server.

Check an image file’s intrinsic width and height before upload using createImageBitmap, while keeping server-side validation as the security boundary.

Load the second select list from an API when the first selection changes, with cancellation and safe DOM updates.

Copy text with the asynchronous Clipboard API and provide clear success and failure feedback.

Preview a selected image with an object URL and release the temporary browser resource afterward.