Order of classes in CSS file matter to jQuery?

Its no surprise that jQuery is becoming the latest poison for all Web Developers these days. I am no JavaScript expert, but jQuery makes even a scripting chimp like me to do some cool stuff without writing too much script! I had been playing with this library for some time and came across this small issue which took about an hour of head scratching. In my jQuery, I was adding a hover class to a <div> element. Here is the <div> as in the markup.

<div id="myDiv" class="Sample">

Here is the Sample class

background-position: 0px -141px;
Here is another class which I am going to add with jQuery.

background-position: 0px -218px;

And finally, here is my jQuery,


This did not work until I figured out why!!!! In my CSS file the Sample-hover class was declared before Sample class. Due to this, the CSS properties were not being overridden as expected. Phew!! I wished I was a good at these things. Sigh!!


Anjanesh said...

You got it all wrong. Order of classes don't matter.
When you do an addClass, its adds a class to the element. myDiv now contains Sample and Sample-hover.
Its now : <div id="myDiv" class="Sample Sample-hover">Stuff</div>

1. You are looking for the jQuery's toggleClass method - not addClass. Or use removeClass when using addClass.

2. You may not need JavaScript for what you are trying to do. Simply replace .Sample-hover with .Sample:hover Check out CSS Pseudo classes.

Abhang Rane said...

I was skeptical about this in the first place. By the way, why did the hover effect start working once I put the .Sample-hover class after .Sample? I guess my point was to explain why addClass failed in my case. Somehow the background position property was not been detected on hover!
I know about the CSS pseudo classes but situations asked me to use Javascript.

Anjanesh said...

"By the way, why did the hover effect start working once I put the .Sample-hover class after .Sample"
Because the class which then becomes class="Sample Sample-hover" and then
.Sample-hover has overridden .Sample

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