crew_admin/public/bower_components/jquery-validation/src/additional/mobileNL.js

$.validator.addMethod( "mobileNL", function( value, element ) {
	return this.optional( element ) || /^((\+|00(\s|\s?\-\s?)?)31(\s|\s?\-\s?)?(\(0\)[\-\s]?)?|0)6((\s|\s?\-\s?)?[0-9]){8}$/.test( value );
}, "Please specify a valid mobile number" );