function showObj(obj)
	{
		obj.style.visibility = 'visible';
	}
	
	function hideObj(obj)
	{
		obj.style.visibility = 'hidden';
	}
	
	function centreObj(obj)
	{
		ns4 = (document.layers)? true:false
		ie4 = (document.all)? true:false

		var scW, scH, obW, obH;
		if (ie4) {
			scW = parseInt(document.body.clientWidth);
			scH = parseInt(document.body.clientHeight); }
		else {
			scW = parseInt(screenSize.width);
			scH = parseInt(screenSize.height); }
			
		obW = parseInt(obj.style.width);
		obH = parseInt(obj.style.height);
		
		obj.style.left = (scW/2)-(obW/2)-100 + 'px';
		obj.style.top = (scH/2)-(obH/2) + 'px';
	}
	
	function centreOffsetObj(obj,xOff,yOff)
	{
		ns4 = (document.layers)? true:false
		ie4 = (document.all)? true:false

		var scW, scH, obW, obH;
		if (ie4) {
			scW = parseInt(document.body.clientWidth);
			scH = parseInt(document.body.clientHeight); }
		else {
			scW = parseInt(screenSize.width);
			scH = parseInt(screenSize.height); }
			
		obW = parseInt(obj.style.width);
		obH = parseInt(obj.style.height);
		
		obj.style.left = (scW/2)-(obW/2)+parseInt(xOff) + 'px';
		obj.style.top = (scH/2)-(obH/2)+parseInt(yOff) + 'px';
	}