title: Understanding the evaluate function in CasperJS
body: <p>I want to understand in which case I should or have to use the <code>evaluate</code> function. </p>
  
  <p>I have read the API doc about the <code>evaluate</code> function of CasperJS, but I'm unsure in which case I should use this function. And what does DOM context mean? Can somebody provide an example?</p>