/**
 * Empty field
 */
function empty_field(el) {
	if(el.value == 'sähköpostiosoite')
		el.value = '';
}

function open_rules() {
	var popup = window.open('rules.html','','scrollbars=yes,menubar=no,height=450,width=500,resizable=yes,toolbar=no,location=no,status=no');
}

function show_invitation_form() {
	if(el = document.getElementById('invitation_form')) {
		el.style.display = 'block';
		el.friend_1.focus();
	}
}