title: PHP Validate string characters are UK or US Keyboard characters
body: <p>What is the easiest or best way in PHP to validate true or false that a string only contains characters that can be typed using a standard US or UK keyboard with the keyboard language set to UK or US English?</p>
  
  <p>To be a little more specific, I mean using a single key depression with or without using the shift key. </p>
  
  <p>I think the characters are the following. 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz~`!@#$%^&amp;*()_-+={[}]|\:;"'&lt;,>.?/£ and Space</p>