/**
 * Validates if the user name field was filled.
 * Empties the user and password field if focused.
 */
var LoginFormValidator = new Class({
	/**
	 * Sets up the event listeners.
	 */
	initialize: function() {
		var user = $('user');
		var pass = $('pass');
		if ($chk(user) && $chk(pass)) {
			//var form = pass.getParent().getParent();
			var form = pass.getParent('form');
			if ($chk(form)) {
				user.addEvent('focus', this.clearField.bind());
				pass.addEvent('focus', this.clearField.bind());
				form.addEvent('submit', this.checkFieldFilled.bind(user));
			}
		}
	},
	/**
	 * Clears the targeted field if user or password field.
	 */
	clearField: function(e) {
		if ((e.target.get('id') == 'user' && e.target.get('value').trim() == 'Benutzername:') || (e.target.get('id') == 'pass' && e.target.get('value').trim() == 'Passwort:')) {
			e.target.set('value', '');
		}
	},
	/**
	 * Checks if the targeted field is filled.
	 */
	checkFieldFilled: function(e) {
		if (this.get('value').trim().length == 0) {
			alert('Bitte geben Sie einen Benutzernamen ein!');
			return false;
		}
	}
});
window.addEvent('domready', function() {
	new LoginFormValidator();
});