function submitForm()
{
  var year= document.mainForm.caryear.options[ document.mainForm.caryear.selectedIndex ].text;
  var carmake= document.mainForm.carmake.options[ document.mainForm.carmake.selectedIndex ];
  if( document.mainForm.carmodel.value== "" )
  {
    alert( "Please fill up the car model field first!" );
    return false;
  }
  if( year== "" )
  {
    alert( "Please select the year of your car" );
    return false;
  }

  if( carmake.value== "" )
  {
    alert( "Please select the car make first!" );
    return false;
  }

  document.mainForm.amount.value="56";
  var s= carmake.value;
  if( s== "TOY" )
    document.mainForm.amount.value="61";
  document.mainForm.item_name.value="GROM-"+ s;
  document.mainForm.os0.value= carmake.text+ ' '+ year+ ' '+ document.mainForm.carmodel.value;
  document.mainForm.submit();
  return true;
}