function expand(id)
{
	img_element_id='exp_'+id;
	
	if (readCookie(id)) {
		document.getElementById(id).style.display = readCookie(id);
	}

	//document.getElementById(id).style.display = readCookie(id);

	if (document.getElementById(img_element_id)) {
		document.getElementById(img_element_id).src = readCookie(img_element_id);
	}

	if (document.getElementById(id).style.display != 'none') {
		document.getElementById(id).style.display = 'none';
		if (document.getElementById(img_element_id)) {
			document.getElementById(img_element_id).src = 'http://www.geodata.soton.ac.uk/doclib/doclib2/plus.png';
		}
	} else {
		
		document.getElementById(id).style.display = 'block';
		if (document.getElementById(img_element_id)) {
			document.getElementById(img_element_id).src = 'http://www.geodata.soton.ac.uk/doclib/doclib2/minus.png';
		}
	}

	createCookie(id,document.getElementById(id).style.display,3600);
	if (document.getElementById(img_element_id)) {
		createCookie(img_element_id,document.getElementById(img_element_id).src,3600);
	}
}


function createCookie(name,value,seconds)
{
	if (seconds)
	{
		var date = new Date();
		date.setTime(date.getTime()+(seconds*1000));
		//var expires = "; expires=Thu, 01-Jan-70 00:00:01 GMT";
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";

}

function readCookie(name)
{
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++)
	{
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name)
{
	createCookie(name,"",-1);
}