Yii2 form extra validations.js

// If it returns false, validation stops here (and afterValidate event will not be called)
$('form').on('beforeValidate', function(event, messages, deferreds) {
	
	var extraConditionsSuccess = false;
	
	/*
	 * Verify extraConditionsSuccess
	 */

	// if false, afterValidate event will not be called	
	return extraConditionsSuccess;

});

$('form').on('afterValidate', function(event, messages, errorAttributes) {
	
	// Disable submit button to avoid multiple submits
	if (errorAttributes.length == 0) {
		$(this).find('input[type=submit]').attr('disabled', 'disabled');
		$(this).find('input[type=submit]').addClass('disabled');
	}
});