function dropdown(sel){
   if(sel.options.selectedIndex == 0){
      alert('Please choose an option');
      return false;
   }
   else{
      c = confirm('You chose ' + sel.options[sel.selectedIndex].value + '\nDo you want to continue?');
      
      if(c){ sel.form.submit(); } else{ sel.selectedIndex = 0; }
   }
}
</script>