title: RegEx for including alphanumeric and special characters
body: <p>I have requirement to allow alphanumeric and certain other characters for a field. I am using this regular expression:</p>
  
  <pre><code> "^[a-zA-Z0-9!@#$&amp;()-`.+,/\"]*$".
  </code></pre>
  
  <p>The allowed special characters are<code>!  @  #  $  &amp;  (  )  -  ‘  .  /  +  ,  “</code></p>
  
  <p>But when I test the pattern with a string "test_for_extended_alphanumeric" , the string passes the test. I don't have <code>"_"</code> allowed in the pattern. What am I doing wrong?</p>