function updateDisplay($res)
{
	var arr = $res.split("\n");
	for (var i=0; i < arr.length; i++)
	{
		var unit=arr[i].split("|");
		if ( unit[0] )
		{
			setState(unit[0], unit[1]);
		}
	}
}

function setState($mac, $state)
{
	var $element=document.getElementById("m_" + $mac);
	if ( $element )
	{
		var $color;
		if ( $state == 0 ) { $color="red"; } else { $color="green"; }
		$element.src=$element.src.replace(/red|green/,$color);
	}
}

function execUpdate($room,$target, $state) {
	if ( $target == "room" ) {
		var todo="";
		for(i=0; i<document.images.length; i++) {
			var image = document.images[i];
			if ( image.id.length == 19 ) {
				if ( image.src.search("teacher") > 0 ) {
					if ( $state == 1 ) {
						todo = todo + "\n" + image.id.substring(2) + "|" + $state;
					}
				}
				else {
					todo = todo + "\n" + image.id.substring(2) + "|" + $state;
				}
			}
		}
		updateDisplay(todo);
		return false;
	}

	updateDisplay($target + "|" + $state);
	
	return false;
}

function toggleState($room,$mac)
{
	var $state = document.getElementById("m_" + $mac).src.search(/green/);
	if ( $state==-1 ) { $state=1; } else { $state=0; }
	return execUpdate($room,$mac, $state);
}