JavaScript (edit)
Getting the ID of the element that fired an event
event.target.id
https://stackoverflow.com/questions/48239/getting-the-id-of-the-element-that-fired-an-event
https://stackoverflow.com/questions/2490825/how-to-trigger-event-in-javascript
How to Use Different CSS Style Sheets For Different Browsers (and How to Hide CSS Code from Older Browsers)
https://developer.mozilla.org/en-US/docs/Web/CSS/appearance (HAY)
Handling CSS prefixes
Another set of problems comes with CSS prefixes — these are a mechanism originally used to allow browser vendors to implement their own version of a CSS (or JavaScript) feature while the technology is in an experimental state, so they can play with it and get it right without conflicting with other browser's implementations, or the final unprefixed implementations. So for example:
- Mozilla uses -moz-
- Chrome/Opera/Safari use -webkit-
- Microsoft uses -ms-
Handling common HTML and CSS problems
https://developer.mozilla.org/en-US/docs/Learn/Tools_and_testing/Cross_browser_testing/HTML_and_CSS
Learn about Flexbox and CSS Grids
Advanced Cross-Browser Flexbox
https://dev.opera.com/articles/advanced-cross-browser-flexbox/
http://particletree.com/features/dynamic-resolution-dependent-layouts/
https://www.thesitewizard.com/css/excludecss.shtml
https://stackoverflow.com/questions/14227531/different-css-for-each-browser
https://www.codeproject.com/Tips/1167666/How-to-Apply-CSS-HACKS-for-Different-Browsers-Chro
https://css-tricks.com/resolution-specific-stylesheets/
CSS Examples
https://dev.opera.com/articles/advanced-cross-browser-flexbox/case-study/
https://css-tricks.com/examples/ResolutionDependantLayout/example-one.php
JavaScript in iFrame
https://stackoverflow.com/questions/13439303/detect-click-event-inside-iframe
https://stackoverflow.com/questions/26285955/how-to-display-an-iframe-on-button-click
https://www.tutorialrepublic.com/faq/how-to-detect-click-inside-iframe-using-javascript.php
https://stackoverflow.com/questions/2381336/detect-click-into-iframe-using-javascript
This is small solution that works in all browsers even IE8:
var elem = document.activeElement; ...