function inputEnter(element, val, leave) {
	if (leave == undefined)
		leave = '';
	if (element.value == val) {
		element.value = leave;
	}
}

function inputLeave(element, val, leave) {
	if (leave == undefined)
		leave = '';
	if (element.value == leave) {
		element.value = val;
	} else if (element.value == '') {
		element.value = val;
	}
}
function validate(email) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   return reg.test(email);
}