select all and remove all with chosen js
$("select").on("chosen:showing_dropdown", function(evnt, params) {
var chosen = params.chosen,
$dropdown = $(chosen.dropdown),
$field = $(chosen.form_field);
if( !chosen.__customButtonsInitilized ) {
chosen.__customButtonsInitilized = true;
var contained = function( el ) {
var container = document.createElement("div");
container.appendChild(el);
return container;
}
var width = $dropdown.width();
var