function show_default(field, default_text, color) {
	if (field.value == '') {
		field.value = default_text;
		color = (typeof(color) != 'undefined') ? color : 'black';
		field.style.color = color;
	}
}

function hide_default(field, default_text, color) {
	if (field.value == default_text) {
		field.value = '';
		color = (typeof(color) != 'undefined') ? color : 'black';
		field.style.color = color;
	}
}