title: Checking if a button exists
body: <p>I have a .js file that is invoked by a few .jsp pages. What I need to do in this particular .js file is to invoke a certain function only if the 'save' button is present in the .jsp page. How do I check if the button exists? Currently, in the .js file the button is referred to this way:
  $('button[id=save]')</p>
  <p>How do I check if such a button exists?</p>