function changeValue($sender) {
	var txtName = document.forms[0].elements['txtName'];
	var txtPass = document.forms[0].elements['txtPass'];
	
	if ($sender == txtName) {
		if (txtName.value == 'username') txtName.value = '';
	}
	if ($sender == txtPass) {
		if (txtPass.value == 'password') txtPass.value = '';
	}
}

function resetValue($sender) {
	var txtName = document.forms[0].elements['txtName'];
	
	if ($sender == txtName) {
		if (txtName.value == '') txtName.value = 'username';
	}

}