Remove remaining Internet Explorer code

[joedolson]

No version of Internet Explorer is still supported by WordPress, but miscellaneous scripts still contain hacks and workarounds to support it. This ticket is to track instances and resolve them.

Known examples:

• Dashed border fix in imgareaselect ​Line 405
• Rest selection area positions in imgareaselect ​Line 350
• Fix background PNGs in farbtastic ​Line 38
• Thickbox hacks ​Line 47, also line 301, 310
• TinyMCE skins effecting galleries and gallery items
• Early exit on autoresize textarea in dashboard.js ​Line 202
• Early exit in customize/controls.js for IE9
• tinymce/plugins/wordpress/plugin.js setting body classes
• Check whether document.msHidden is present in heartbeat.js
• emoji.js browser checks
• twentytwentyone/assets/js/polyfills.js
• gruntfile.js css minification compatibility
• some settings in wp-admin/css/forms.css that are IE specific
• use classlist methods in twentynineteen/js/touch-keyboard-navigation.js & priority-menu.js
• timezone methods in dashboard.js

This is just a rough look at some of the possible issues. None of these are particularly important, but it would enable us to clean up the codebase in a variety of ways by removing exceptions.

[szepe.viktor]

This is a very good idea.

[iflairwebtechnologies]

Remove Legacy Internet Explorer-Specific Code and Clean Up Outdated Scripts in WordPress

[iflairwebtechnologies]

This patch removes legacy Internet Explorer (IE) specific code and cleans up outdated scripts in WordPress, ensuring compatibility with modern browsers.

Changes Made:

• Removed IE-specific hacks in JavaScript and CSS files (e.g., imgareaselect, farbtastic, thickbox, tinymce, heartbeat.js, emoji.js, dashboard.js).

• Cleaned up IE-specific polyfills and workarounds in theme files (twenty-nineteen, twenty-twenty-one).

• Refactored code in functions.php and polyfills.js to remove unnecessary IE support.