wp_dropdown_categories and custom attribute

Question

I'm using this jQuery plugin to handle select element on my site: bootstrap-select

Unfortunately, I can't found any option which allow me add a custom attribute to the select element, for e.g:

I want my dropdown look like this:

<select class="dropdown" data-live-search="true">
...
</select>

Is there any chance for me?

Answer 1

The only filter available is wp_dropdown_cats, which allows you to filter the entire HTML select string and that means trying to string-match markup. That is always a bit questionable. Still...

function dropdown_data_attr_wpse_213033($output){
  return str_replace('<select','<select data-live-search="true"',$output);
}
add_filter('wp_dropdown_cats','dropdown_data_attr_wpse_213033');
wp_dropdown_categories(); // test