function carga(){
var anchors = document.getElementsByTagName("a");
 for (var i=0; i<anchors.length; i++) {
   var anchor = anchors[i];
 if((anchor.className) == "popup"){ 
 anchor.onclick = function() {
        popUp(this.getAttribute("href"));
        return false;
      }

    }
  
  } 
}
function popUp(winURL) {
  window.open(winURL, "Video", "width=355,height=290,top=400,left=700,scrollbar=no,toolbar=no");
}
window.onload = carga;