title: Reg ex to allow only alphanumeric and some other special characters using form input fields?
body: <p>Hi all i like to allow only certain characters by user in form fields like a-z, A-Z, 0-9, -,&amp; and _.</p>
  
  <p>I am poor at regex. what will be the regex function to check whether string contains other than these characters using jquery</p>