function foto(url)
{
	screenWidth = window.screen.availWidth;
	screenHeight = window.screen.availHeight;
	
	windowWidth = 450;
	windowHeight = 300;
	windowLeft = ( screenWidth - windowWidth ) / 2;
	windowTop = ( screenHeight - windowHeight ) / 2;
	
	p=window.open( url, 'zoom1', "left=" + windowLeft + ",top=" + windowTop + ",height=" + windowHeight + ",width=" + windowWidth + ",scrollbars=no");
p.focus();

}