function doUpdate(n)
{  
  new Ajax("assets/snippets/excel_custom/getUnitOptions_response.php",{
  //get all the variable/value pairs from the form
    postBody:$('model_select_'+n).toQueryString(),
    onComplete:showResponse,
    update:$('unit_select_'+n)
  }).request();
}

function doSelect(n)
{
  new Ajax("assets/snippets/excel_custom/getUnitOptions_response.php",{
  //get all the variable/value pairs from the form
    postBody:$('model_select_'+n).toQueryString(),
    onComplete:showResponse2,
    update:$('comp'+n)
  }).request(); 
}
  
function showResponse(request){
}

function showResponse2(request){
}