window.onload = function() {
	document.getElementById('backlink').onclick = function() {
	history.back();
	return false;
	}

	function ChangeTab(tabname) {
	document.getElementById('tab1').style.display = 'none';
	document.getElementById('tab2').style.display = 'none';
	document.getElementById(tabname).style.display = 'block';
	}
	
	document.getElementById('link1').onclick = function() {
	ChangeTab('tab2');
	return false;
	}
	document.getElementById('link2').onclick = function() {
	ChangeTab('tab1');
	return false;
	}
}