non l' hai passato l' esame, eh?
codice:
<script type="text/javascript">
function check(sel,theForm){
  if(sel.selectedIndex!=0){
    var val=sel.options[sel.selectedIndex].value
    if(val=='Gara' || val=='Appalto'){
      theForm.importo.disabled=false;
      theForm.importo_cent.disabled=false;
    }
    else {
      theForm.importo.disabled=true;
      theForm.importo_cent.disabled=true;
    }
  }
  else {
    theForm.importo.disabled=true;
    theForm.importo_cent.disabled=true;
  }
}
</script>