// Adds event to window.onload without overwriting currently 
// assigned onload functions.

function addLoadEvent(func) {    
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } 
  else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}


// set target for external links (rel="external")

function external() { 
  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") == "external")anchor.target = "_blank";
    else if(anchor.getAttribute("href") && anchor.getAttribute("type") == "external")anchor.target = "_blank";
  } 
} 

addLoadEvent(external);