function trim(stringa){
while (stringa.substring(0,1) == ' '){
stringa = stringa.substring(1, stringa.length);}
while (stringa.substring(stringa.length-1, stringa.length) == ' '){
stringa = stringa.substring(0,stringa.length-1);}
return stringa;}

function check_mod(){
   var nome = trim(document.last_mod.ls_n.value);
   var cognome = trim(document.last_mod.ls_c.value);
   var telefono = trim(document.last_mod.ls_tel.value);
   var mail = trim(document.last_mod.ls_ml.value);
   var emailtest = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-]{2,})+\.)+([a-zA-Z0-9]{2,})+$/;
   var testo = trim(document.last_mod.ls_txt.value);

if (nome == '' || nome == 'undefined')
   {
   alert ("Insert name!")
   document.last_mod.ls_n.focus();
   return false;
   }
else if (cognome == '' || cognome == 'undefined')
   {
   alert ("Insert surname!");
   document.last_mod.ls_c.focus();
   return false;
   }
else if ((telefono == '' || telefono == 'undefined')&&(mail == '' || mail =='undefined'))
   {
   alert ("Insert at least one (Phone or E-mail) to be contacted!");
   document.last_mod.ls_tel.focus();
   return false;
   }
else if((mail == '' || mail =='undefined')&&(telefono == '' || telefono == 'undefined'))
   {
   alert ("Insert e-mail address!");
   document.last_mod.ls_ml.focus();
   return false;
   }
else if ((mail != '')&&(!emailtest.test(mail))){
   alert ("Insert a valid mail address!");
   document.last_mod.ls_ml.focus();
   return false;
   }
else if(testo == "" || testo =="undefined")
   {
   alert ("Insert message's text!");
   document.last_mod.ls_txt.focus();
   return false;
   }
else{
var pars = Form.serialize(document.last_mod);
new Ajax.Updater('form_div','js/send_last_en.php',{asynchronous:true, method: 'post', parameters: pars});
}
}

function back_form(){
new Ajax.Updater('form_div','back_form.html',{asynchronous:true});
}