title: Underscore as a JavaScript variable?
body: <p>In <a href="https://stackoverflow.com/questions/3504499/how-to-copy-table-row-with-clone-in-jquery-and-create-new-unique-ids-for-the-con">this post</a>, <a href="https://stackoverflow.com/users/13249/nick-craver">Nick Craver</a> provided an answer in which he used:</p>
  
  <pre><code>function(_, id)
  </code></pre>
  
  <p>This code doesn't declare the underscore as a variable before using it. My search on google and on here only points to references to the use of the underscore as a prefix., not as the variable itself. What does it do? I like the solution by Nick but that bit bothers me.</p>