script.js

jQuery( function($){
	
	// To use for field other than job_region, change job_region to the meta
	// key of the field
	$( '#job_region > .level-0' ).each( function ( index ) {
		$( this ).prop( 'disabled', 'disabled' );
	});

	$( '#job_region' ).trigger( 'chosen:updated' );

});