function validaForm(f){

var v = f['os0'].value;

if(v == null || v == ''){
alert('Device PIN number is required!');
f['os0'].focus();
return false;
}
//alert(v.replace(/[^0-9]/ig,"").replace(/[^a-f]/ig,""));
if( v.length < 8 || v.replace(/[^0-9a-f]/ig,"") != v ) {
alert('Device PIN number is a hexadecimal number with 8 digits.');
f['os0'].focus();
return false;
}
return true;
}