// =============================================================
// = written by tomonaga tokuyama (tomonagatokuyama.com), 2007 =
// =============================================================
Element.addMethods(['INPUT', 'TEXTAREA'], {
	
	setDefaultValue : function (element, value) {
		element = $(element);
		element._default = value;
		element.checkValueSet()
		// element._presentFunc = element.present;
		// element.present = function () {
		// 	value = element.value;
		// 	return (element._presentFunc() && value != element._default);
		// }
		element.observe('focus', function (e) {
				// element = Event.element(e);
				var d = element._default
				element.style.color = '#000';
				if ($F(element) == d)
					element.value = '';
			});
		element.observe('blur', function (e) {
				element.checkValueSet()
			});
			return element;
		},
		clearIfDefault : function (element) {
			element = $(element);
			if (element.value == element._default)
				element.value = '';
		},
		checkValueSet :function (element) {
			element = $(element);
			if (! element.present()) {
				element.value = element._default;
				element.style.color = '#8e8e8e';
			}
		},
		
		errorIfEmpty :function (element, email) {
			element = $(element);
			if (! element.present()) {
				element.value = element._default;
				element.style.color = '#ff6863';
				return true;
			}
			if (email && ! element.value.match(/^[\w\-]+\.?[\w\-]+@([\w\-]+\.)+[\w\-]+$/)) {
				element.style.color = '#ff6863';
				return true;
			}
			return false;
		}
	
	});