title: Jquery control input field
body: <p>How can Jquery control input type="text" 4 digit, if user type 5 digit, the first one will remove to keep 4 digit ?</p>
  
  <p>for example:
  input > A001</p>
  
  <p>if
  input > A0015, change to 0015, the first digit will auto remove</p>