When should I use return false in jquery function?
I found lots of functions like this one:
$(function() {
$("body a").click(function() {
alert(this.innerHTML);
return false;
});
});
What's the difference between this and $(this) in jquery?
They all have a line return false; - I don't know when I should use return false in jquery function and don't know what's the use of it?
Answers:
You're clicking on an anchor, whose default behavior is to navigate somewhere. Returning false may be an attempt to prevent the navigation and keep user on current page/view.
In the scope of the click handler, this is the unwrapped DOM element. $(this) wraps it and returns a jQuery element. It is common practice to wrap this once and make it available within the scope as that, or often $this (prefixing variable names with $ is a convention to indicate a jQuery element).
Your example could therefore be written as
$(function() {
$("body a").click(function() {
var $this = $(this);
alert($this.html());
return false;
});
});
According to jQuery Events: Stop (Mis)Using Return False (archived link), returning false performs three tasks when called:
- event.preventDefault();
- event.stopPropagation();
- Stops callback execution and returns immediately when called.
The only action needed to cancel the default behaviour is preventDefault(). Issuing return false; can create brittle code. Usually you'd want just this:
$("a").on( 'click', function (e) {
// e == our event data
e.preventDefault();
});
And secondly "this" is a DOM element in javascript and "$(this)" is a jQuery element that references the DOM element. Read more on the topic at jQuery's this: demystified.