title: Which characters should be allowed and rejected in a user registration form (name,address,phone,etc)?
body: <p>I'm preparing a user registration form. Most users will be from North America, but it will be available globally.</p>
  <p>The email field will be filtered by PHP filter_var FILTER_VALIDATE_EMAIL.</p>
  <p>Regardless of the filtering method (regex probably), I'd like to know which characters are suggested to be allowed in the form fields (name, street address, city, etc) and which should be either filtered out or trigger a rejection of the form submit.</p>