Add class to select2 element

问题

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');

回答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.

回答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

回答3:

According to the documentation, containerCssClass is only a constructor property. The best you're probably going to be able to do is reinitialize it when you get an error via:

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

Note from comments: If you get Uncaught Error: No select2/compat/containerCss(…), you need to include the select2.full.js version instead of the basic one

回答4:

For those wandering here from google, the property containerCssClass has a misleading name since it doesn't actually add any classes to the container element, but rather to the selection element. You can see this when you inspect the generated html.

I came across a nice little hack here that allows you to apply your css class to the container by adding it to the theme property, like so:

$('#my-select').select2({
    theme: "bootstrap myCssClass",
});

回答5:

use theme option.

 $(".select").select2({
        placeholder: "",
        allowClear: false,
        theme: "custom-option-select"
    });

回答6:

Easiest way:

Create a parent class like

<div class="select-error">
    <select id="select2" name="select2" data-required class="form-control">
        <option value="" selected>No selected</option>
        <option value="1">First</option>
        <option value="2">Second</option>
    </select>
</div>

when you validate it with jquery or php just add style or css to .select-error class like

style="border:1px solid red; border-radius: 4px"

jQuery example:

$('[data-required]').each(function() {
  if (!$(this).val()) {
    if ($(this).data('select2')) {
      $('.select-error').css({
        'border': '1px solid red',
        'border-radius': '4px'
      });
    }
  });

回答7:

You can use dropdownCssClass opiton

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

来源：https://stackoverflow.com/questions/15028995/add-class-to-select2-element

标签

jquery

jquery-select2