Return false; and e. preventDefault ();

Have you ever seen those two things (in the title) being used in jQuery? Here is a simple example:
Copy codeThe Code is as follows:
$ ("A"). click (function (){
$ ("Body"). append ($ (this). attr ("href "));
Return false;
}

That code wocould append the href attribute as text to the body every time a link was clicked but not actually go to that link. the return false; part of that code prevents the browser from grouping the default action for that link. that exact thing cocould be written like this:
Copy codeThe Code is as follows:
$ ("A"). click (function (e ){
$ ("Body"). append ($ (this). attr ("href "));
E. preventDefault ();
}

So what's the difference?


The difference is that return false; takes things a bit further in that it also prevents that event from propagating (or "bubbling up") the DOM. the you-may-not-know-this bit is that whenever an event happens on an element, that event is triggered on every single parent element as well. so let's say you have a box inside a box. both boxes have click events on them. click on the inner box, a click will trigger on the outer box too, unless you prevent propagation. like this:

Demo address: http://css-tricks.com/examples/ReturnFalse/
So in other words:
Copy codeThe Code is as follows:
Function (){
Return false;
}

// IS EQUAL

Function (e ){
E. preventDefault ();
E. stopPropagation ();
}

It's all probably a lot more complicated than this and articles like this probably explain it all a lot better.

Refer:

1. The difference between 'Return false; 'and 'E. preventDefault ();'
2. Event order

Package and download test code