libSREV - a simple and clean way to add input regex validation to a html form

libSREV

/*
 * libSREV - Simple Regular Expression Validation
 * ==============================================
 * 
 * Author: notuxic
 * Version: 0.1
 * License: WTFPL (Do What The Fuck You Want To Public License)
 * 
 *         DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE 
 *                    Version 2, December 2004 
 *
 * Everyone is permitted to copy and distribute verbatim or modified 
 * copies of this license document, and changing it is allowed as long 
 * as the name is changed. 
 *
 *            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE 
 *   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 
 *
 *  0. You just DO WHAT THE FUCK YOU WANT TO.
 *
 */


/*
 * Usage:
 * ------
 * simply add a "rev" attribute with a ECMA-Script regular
 * expression as value to the tag you want to validate.
 *
 * Example:
 * --------
 * Desired Format: yy-mm-dd
 * <input type="text" rev="[0-99]{1}-[1-12]{1}-[1-31]{1}" name="date" />
 * 
 * Styling:
 * --------
 * simply use the following two classes for styling a tag
 * depending on the validation result:
 * 	.rev-correct
 * 	.rev-incorrect
 * 
 * CSS-Tip:
 * --------
 * use the :focus selector to only style the active tag
 * depending on the validation result.
 * 
 */


function validateRE() {
	var activeelem = document.activeElement;
	var pattern = new RegExp(activeelem.getAttribute('rev'),'m');
	var string = activeelem.value;
	var result = pattern.test(string);
	if (result == true) {
		activeelem.classList.remove('rev-incorrect');
		activeelem.classList.add('rev-correct');
	}
	else {
		activeelem.classList.remove('rev-correct');
		activeelem.classList.add('rev-incorrect');
	}
}


function registerREV() {
	var taglist = document.getElementsByTagName('*');
	for (i = 0; i < taglist.length; i++) {
		if (taglist[i].getAttribute('rev')) {
			taglist[i].addEventListener('keyup', validateRE, false);
		}
	}
}


registerREV();