Add class to select2 element

Question

The documentation is either terrible or I'm missing something. I'm trying to add an error class to a select2 box for form validation. It's just a 1px red border.

I found the containerCssClass method in the documentation, but I'm not sure how to apply it.

I have tried the following with no luck:

$("#myBox").select2().containerCssClass('error'); 

Answer 1

jQuery uses JSON objects to initialize, so I guess this one will as well:\

$("#myBox").select2({ containerCssClass : "error" }); 

If you want to add/remove a class you can do this after you initialized it

$($("#myBox").select2("container")).addClass("error"); $($("#myBox").select2("container")).removeClass("error"); 

The above function gets the DOM node of the main container of select2 e.g.: $("#myBox").select2("container")

Important
You will need to use the container method to get the container since you won't edit the SELECT directly but select2 will generate other HTML to simulate a SELECT which is stylable.

Answer 2

For already initialized select2 element I have tried @Niels solution but it resulted in an error: Uncaught TypeError: Cannot read property 'apply' of undefined

Went into the source and this has been working instead:

$('#myBox').data('select2').$container.addClass('error') $('#myBox').data('select2').$container.removeClass('error') 

Using select2 v4.0.3 full