function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      };
      func();
    }}}
// funció per obrir links en "_blank" amb l'atribut rel="extern"
		function externalLinks() { 
		 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") == "extern") 
		     anchor.target = "_blank"; 
		 } } 
		addLoadEvent(externalLinks);