function disableFirstOptions() {
	var selects = document.getElementsByTagName('select');
	for(var i = 0; i < selects.length; ++i) {
		hide( selectedOption(selects[i], 0), 'first' );
	}
}

function selectedOption(select, index) {
	return select.getElementsByTagName('option')[typeof(index) == 'undefined' ? (select.selectedIndex || 0) : index];
}

function hide(node, extra) {
	var classes = (node.className || '').split(' ');
	classes.push('disabled');
	if(extra) classes.push(extra);
	node.className = classes.join(' ');
	node.disabled = true;
}

function unhide(node) {
	node.disabled = false;
	node.className = node.className.replace(/ ?disabled/, '');
}