Uncaught ReferenceError: $ is not defined?

Essential steps to troubleshoot the error

To fix the issue, take the following steps, one by one:

1. Check the order: Make sure any script that depends on jQuery is inserted after the jQuery script link in your HTML.
2. Script tag check: Verify the path in the src attribute of the jQuery script tag is correct.
3. Load verification: Check the browser console for 404 errors. If you see one, your jQuery file isn't loading correctly.
4. CDN or local: Using a CDN like Google's for jQuery may increase your site's performance and reliability.
5. Conflict handling: Using jQuery.noConflict(), you can avoid conflicts with other libraries that use the $ symbol.

Following these steps is a pretty good way to identify and fix issues. After all, us developers "bug-fix" in our sleep, right? 😅

Cross-browser compatibility

Just like running a marathon, you should take a few rounds of your webpages in different browsers to see if they behave correctly.

Let the SRCTM face-off begin: (SRCTM = Script-Reference to Compatibility Test; invented here, don't google it)

1. Test all fronts: Ensure that your website runs smoothly in various browsers. Yes, including that one browser everyone loves to ignore (internet explorer).
2. Protocol: Make sure the src in script tag starts with either http or https. You wouldn't want your website to be a cause of mixed content issues, would you? Get your gears straight. 🚀

If even after all these wonders of modern debugging techniques, you still encounter issues, return to the Oracle (AKA jQuery documentation or jQuery communities) for further enlightenment. 🧙‍♀️🔮

Mixing multiple scripts & resolving conflicts

Just like mixing ingredients in a recipe, you need the right order for your scripts too.

1. Puzzle pieces together: If you are running multiple scripts, place them in an order that avoids conflicts.
2. Load after jQuery: When working with jQuery plugins, include them after the jQuery library but before your own custom scripts.
3. Ready, Steady, Go: Always wrap your jQuery code within the $(document).ready(...) function. This ensures you don't start the party before all the guests (DOM elements) have arrived. 🎉

By managing your scripts sequence and dependencies, you can avoid a lot of 'what the duck 🦆' moments while dealing with JavaScript.