REGEX - must contain alphanumeric and slash

Question

I am trying to do a validation that an input field must contain alpha numeric and slash as its value.

Eg: AA/AB/12314/2017/ASD

The above shown is the example of

Answer 1

escaping / like \/is a good practise but inside of char class, not necessary.
the * must be changed to +. because * will also match null.
also remove the - otherwise - will also be matched.

function validate(){
  var message = $('#message').val();

  if (/^[a-zA-Z0-9/]+$/.test($.trim(message)) == false){
      $('#message').focus();
     alert('invalid message');
  }
}

Test