function op(url) {	
  day = new Date();
  ancho = 680;
  alto = 500;
  id = day.getTime();
  links = screen.width/2-(ancho/2);
  oben = screen.height/2-(alto/2);
  pageo = "window.open('" + url + "', '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=1,width=' + ancho + ',height=' + alto + ',left=' + links + ',top=' + oben);";
  page = "page" + id;
  eval(page =  pageo);
}

function soja_perdida() {	
  day = new Date();
  ancho = 740;
  alto = 550;
  id = day.getTime();
  links = screen.width/2-(ancho/2);
  oben = screen.height/2-(alto/2);
  pageo = "window.open('calculo_perdida_pisadas.htm', '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=1,width=' + ancho + ',height=' + alto + ',left=' + links + ',top=' + oben);";
  page = "page" + id;
  eval(page =  pageo);
}

function extraLinks() {
if (!document.getElementsByTagName) return; 
var anchors = document.getElementsByTagName("a"); 
for (var i=0; i<anchors.length; i++) { 
	var anchor = anchors[i]; 
	if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "extra") 
	anchor.target = "_blank";
	}; 
};

function init() {	
	extraLinks();
};

window.onload = init;