document.getElementsByClassName = function(cl) {
	var retnode = [];
	var myclass = new RegExp('\\b'+cl+'\\b');
	var elem = this.getElementsByTagName('*');
	for (var i = 0; i < elem.length; i++) {
		var classes = elem[i].className;
		if (myclass.test(classes)) retnode.push(elem[i]);
	}
	return retnode;
};

function show( where )
{
	var c1, c2;
	var els, i;
	switch( where )
	{
	case "au":
		c1 = "address_os";
		c2 = "address_au";
		break;
	case "os":
		c1 = "address_au";
		c2 = "address_os";
		break;
	}
	els = document.getElementsByClassName( c1 );
	for( i=0; i<els.length; i++ )
	{
		els[i].className = c1 + " hide";
	}
	els = document.getElementsByClassName( c2 );
	for( i=0; i<els.length; i++ )
	{
		els[i].className = c2;
	}
	els = document.forms[0].elements['location'];
	for( i=0; i<els.length; i++ )
	{
		if( els[i].value == where )
		{
			els[i].checked = true;
		}
	}
	return false;
}