如何检查是否已输入任何不允许使用php的字符

Question

Suppose I have a form and in the form, there is an input field for the users to put their full names. I want only characters (A-Za-z) and spaces to be submitted by the users.

<form action='page2.php'>
    <input type='text' name='fullname'>
    <input type='submit' name='submit' value='Submit'>
</form>

I know, it can be done by html. But I want to check in page2 if user has typed anything without (A-Za-z) and spaces. How this check can be performed with php?

Answer 1

Try this

if (!preg_match("/^[a-zA-Z]$/", $user)) {
    /// not match
}