document.write ad voodoo

loadAd.js

function loadAd(url, div) {
  function makeAdParser(el, cb) {
    var inNoScriptTag = false;
    var parser = function(txt) {
      txt = txt.trim();

      if(txt === '</noscript>') { inNoScriptTag = false; return; }
      if(txt === '<noscript>') { inNoScriptTag = true; return; }
      if(inNoScriptTag) { return; }

      if(txt.indexOf('<scr') === 0) {
        // Load the script
        $('body').append(txt);
      } else if(txt.indexOf('<a') === 0) {
        // Hey look, its the AD "finally"
        // Append it to the div
        div.html(txt);
        // Report back home
        cb();
      }
    };
    return parser;
  }

  var dw = document.write;
  document.write = makeAdParser(div, function() { document.write = dw; });
  var adScript = $('<script/>').attr('src', url);
  $('body').append(adScript);
}