function checkreferrer(){
  var selectorValue = selector.value;
  if (selectorValue.indexOf('specify')>0) {holder.appendChild(rBox);}
  else {
      holderChildren = holder.childNodes;
      if (holderChildren.length>0) {
         holder.removeChild(rBox);
         rBox.value='Please specify...';
      }
  }
}

function addEvent(obj, evType, fn, useCapture){
  if (obj.addEventListener){
    obj.addEventListener(evType, fn, useCapture);
    return true;
  } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  } else {
    obj['on'+evType]=fn;
    return true;
  }
}


// as soon as we get to the function we need to create the option box, but not instantiate it

var holder = document.getElementById('referrerboxholder');
var rBox = document.createElement("input");

rBox.setAttribute('name','other');
rBox.setAttribute('class','specify');
rBox.setAttribute('id','other');
rBox.setAttribute('value', 'Please specify...');
rBox.setAttribute('onClick','if (this.value==\'Please specify...\') this.value=\'\';');

var selector = document.getElementById('referrerselect');

addEvent(selector,'change',checkreferrer,false);