function check_modform(){
  var errs = 0;
  var from_email = document.moddata_form.from.value;
  if(!check_email_validity(from_email)){
    alert("You must specified a valid email address.");
    errs++;
  }
  if(document.moddata_form.request.value.length<10){
    alert("You must specified a valid request.");
  }
  return (errs==0);
}

function check_email_validity(email){
   if(email.length>0){
     var fld = trim(email);
     var emailString = new RegExp("^([_a-z0-9-]+)(\\.[_a-z0-9-]+)*@([a-z0-9-]+)(\\.[a-z0-9-]+)*(\\.[a-z]{2,4})$");
     if (!emailString.test(fld)){
       return false;
     }else{
       return true;
     }
   }
   return false;
}

function trim (myString){
 return myString.replace(/^\s+/g,'').replace(/\s+$/g,'')
}