var SearchField = {
  focus: function() {
    this.style.background = "#ffffff";
  },

  prepare: function() {
    form = document.getElementById("searchform");
    elems = form.getElementsByTagName("INPUT");
    for (i = 0; i < elems.length; i++) {
      el = elems[i];
      if (el.type == "text" && el.name == "s")
        if (el.value == "")
          el.onfocus = SearchField.focus; 
        else
          el.style.background = "#ffffff";
    }
  },

  register: function() { DocGen.doOnLoad(SearchField.prepare); }
}

SearchField.register();