handling errors

[sjm]

I have been asked to work on a web site using PHP and have never used this language before.
I also have tried to find an answer for my question by searching many sites but have had no luck so far.
Does anyone know how to ask a person to enter their last name on a form but not allow them to use the following symbols ~!@#$%^&*.
How do I reject these entries and allow them to try again?

Thank you so much for any help you can provide!!
sjm 😕

[Buddha443556]

It's looks like all you want is alphanumerics "a-zA-Z_0-9" which are nice and safe.

First you could start on the client-side with a javascript:

function isEmpty(inputStr) {
  if (inputStr == null || inputStr == "") {
    return true
  }
  return false
}
function isUserID(inputStr) {
  if (/\W/.test(inputStr)){ 
    return (false)
  }
  return (true)
}
function checkForm(form) {
  if(isEmpty(form.userid.value)){
	alert("Please enter a User ID.")
	return false
  }
  if(!isUserID(form.userid.value)){
	alert("User ID should only contain letters, numbers and underscore characters..")
	return false
  }
}

and in the form's event handler is the following:
... onSubmit="return checkForm(this)" ....

Sever-side not much different:

if($_POST['userid']){
  if(preg_match ("/\W/", $_POST['userid'])) {
    // error in userid
  } else {
    // no error what's next
  }
}

The \W matchs nonword characters, which you could change to "~!@#$%^&*" if you want. (might need to escape a couple of those symbols)

Hope that helps?