/*
 * Sets default value of input and clears it on focus.
 * Useful for search or newsletter forms.
 * @param (string) defaultVal - default value to set
 * @param (optional) (string) defaultClass - class to add when
 *     the input has no value entered (other than the default)
 * @param (optional) (string) nonDefaultClass - class to add
 *     when the user entered his/her own value
 */	
$.fn.defaultVal = function(defaultVal, defaultClass, nonDefaultClass) {
	return this.each(function() {
		var $input = $(this);

		// store the original val() implementation
		$input._val = $input.val;

		// replace it with an upgraded one
		$input.val = function(newVal) {

			// if there was value specified, act as setter
			if (typeof newVal != "undefined") {
				this._val(newVal);
				return this;
			}
			// otherwise - as getter
			else {
				// use original getter
				var val = this._val();
				// return empty value if it's the default
				return (val === defaultVal) ? '' : val;
			}
		};


		// If the input has no initial value,
		// set it to default and (optionally) add a default class
		if ($input.val() === '') {
			$input.val(defaultVal);
			if (defaultClass)
				$input.addClass(defaultClass);
		}


		$input.focus(function() {
			// On focus set real value
			$input.val($input.val());
			if (defaultClass) {
				$input.removeClass(defaultClass);
			}
			if (nonDefaultClass) {
				$input.addClass(nonDefaultClass);
			}
		}).blur(function() {
			// On blur - set default if the value is empty
			if ($input.val() == '') {
				$input.val(defaultVal);
				if (defaultClass) {
					$input.addClass(defaultClass);
				}
				if (nonDefaultClass) {
					$input.removeClass(nonDefaultClass);
				}
			}
		});


		// set the real value on form submit
		var $form = $input.closest('form');
		if ($form.length) {
			$form.submit(function() {
				$input.val($input.val());
			});
		}
	});
};