What is return false?

Decoding return false in JavaScript: A More Human Approach

So, you’ve stumbled across return false in your JavaScript code, huh? It looks simple enough, but trust me, it’s got a bit more going on under the hood than you might think. It’s one of those things that can trip you up if you don’t really get it. Let’s break it down, shall we?

Basically, return false is a JavaScript statement that’s like hitting the brakes on a function. First off, it stops the function dead in its tracks – like pulling the emergency cord on a train. Anything after that return false? Doesn’t get executed. Kaput.

Secondly, it sends back a value – specifically, the boolean value false – to whoever called the function. Think of it as a “nope, didn’t work” signal. The code that called the function can then use that signal to figure out what to do next.

return false and Event Handlers: Where Things Get Interesting

Now, here’s where it gets a little more interesting, especially if you’re digging through older code or using jQuery. You’ll often see return false hanging out in event handlers. These are the functions that spring into action when something happens – a user clicks a link, submits a form, that kind of thing.

Back in the day, return false was kind of a Swiss Army knife. It did a couple of extra things:

The Modern Way: Being More Explicit

These days, we have better tools for the job: event.preventDefault() and event.stopPropagation(). They’re more specific and give you more control.

• event.preventDefault(): This only stops the default behavior. It’s like saying, “Don’t do the default thing, but let everyone else know something happened.”
• event.stopPropagation(): This only stops the event from bubbling up. “Keep this event to yourself, kid.”

Why are these better? Well, for starters, they’re clearer. You know exactly what you’re doing. Plus, they give you more control. Maybe you want the event to bubble up, but you don’t want the default action. With these methods, you can do that.

jQuery’s Little Secret

Okay, quick jQuery note: In jQuery, return false does act like it’s calling both event.preventDefault() and event.stopPropagation(). So, it’ll still work. But, even in jQuery-land, it’s a good idea to get into the habit of using the explicit methods. It just makes your code easier to understand, especially if you’re working with other people or might move away from jQuery later on.

So, Should You Use return false?

• If you’re knee-deep in old code: You’ll probably see it. Just know what it’s doing.
• In modern JavaScript: Probably not. return false by itself won’t prevent the default behavior or stop propagation. Use the event methods instead.
• AJAX forms: event.preventDefault() is your friend.

Examples in the Wild

Stopping a link:

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