Number field, only numbers no other charachters

I’m currently using this to allow only numbers, but I would like to do it server side with one of CF7’s filters:

$('.license').keypress(function(e){    
                var charCode = (e.which) ? e.which : event.keyCode    
                if (String.fromCharCode(charCode).match(/[^0-9]/g))    
                  return false;                        
    
            });    
	
	

See Custom validation

@danstramer – did you ever figure this out?

I need the same!

forgot to click notify lol