How I can do a form validation (HTML5 Required) with Select2?
This may be a late answer but anyway : you just add a required to the select and the html5 validation will show up :
Fiddle : http://jsfiddle.net/mksshhwt/
<form>
required select2: <select class="select2" required multiple name="test">
<option>Test</option>
<option>Test2</option>
</select>
<br/>
required select2: <select class="select2" required name="test">
<option>Test</option>
<option>Test2</option>
</select>
<br/>
<input type="submit" value="Test" />
</form>
JS :
$(".select2").select2();
you may get the validation a little on the top , follow this thread to fix it : https://github.com/select2/select2/issues/128