function resetField(textbox, defaultString) 
{
  if (textbox.value == defaultString) {
    textbox.value = '';
  }
}

function disableModel(dropdownlist) 
{
  var dropDown = document.getElementById(dropdownlist);
  if (dropDown != null) {
    dropDown.disabled = true;
    for (i = 0; i < dropDown.options.length; i++ ) {
      if (dropDown.options[i].selected == true) {
        dropDown.options[i].text = "Loading Models...";
      }
    }
  }
}