function defaultRegionValue() {
	var region = document.getElementById('region');
	if (region.value == '' || region.value == ' ')
	{
		region.value = 'Click to enter a region' 
	}
}


function toggleOverlay(overlayid) {
	if (overlayid=='compare') {
		closeHighlight();
	}
	var overlaystatus = document.getElementById(overlayid);
	var screenstatus = document.getElementById("windowscreen");

	if (overlaystatus.style.display == 'block') {
		overlaystatus.style.display = 'none';
		screenstatus.style.display = "none";
	}
	else {
		overlaystatus.style.display = "block";
		screenstatus.style.display = "block";
	}
}

function selectRegion(region) {
	changeRegion(region);
	toggleOverlay('regions');
}

function changeRegion(region) {
	if (!region) {
		var region = document.getElementById("region").value;
	}
	setRegion(region);
}

function setRegion(region) {
	http=GetXmlHttpObject();
	if (http==null)
	{
		alert ("Browser does not support HTTP Request");
		return;
	} 
	var url="get_region_data.php";
	url=url+"?region="+region;

	http.open("GET",url,true);
	http.onreadystatechange = function() 
	{
		if (http.readyState == 4) 
		{      
			var jscript = http.responseText;
    	    var region_data;
        	eval(jscript);
		
			var region = region_data.region_name;
			document.getElementById("region").value=region; 

			var ref = region_data.ref;
			document.getElementById("ref").value=ref; 
			
			var zone = region_data.utm_zone;
			document.getElementById("zone").value=zone; 
			
			var center_lat = region_data.center_lat;
			document.getElementById("center_lat").value=center_lat; 
			
			var center_lng = region_data.center_lng;
			document.getElementById("center_lng").value=center_lng; 
			
			var ui_scale = region_data.ui_scale;
			document.getElementById("ui_scale").value=ui_scale; 
			
			getRegionTitle(region);
		//	getMapTitle(1);
			getMap(1);
			getLegend(1);
		//	getMapTitle(2);
			getMap(2);
			getLegend(2);
					
		}
	}
	http.send(null);

}