function WriteLayer(ID,parentID,URL) {
  if (document.layers) {
  var oLayer;
  if(parentID){
  oLayer = eval('document.' + parentID + '.document.' + ID + '.document');
  }else{
  oLayer = document.layers[ID].document;
  }
  oLayer.open();
  oLayer.write(URL);
  oLayer.close();
  }
  else if (parseInt(navigator.appVersion)>=5&&navigator.
  appName=="Netscape") {
  document.getElementById(ID).innerHTML = URL;
  }
  else if (document.all) document.all[ID].innerHTML = URL
}

<a href="javascript:WriteLayer('ctd',null,'testing')">blablabla</a>
<div class='ctd'></div>