title: Jquery/Javascript : Negative of a Variable
body: <p>What's the best way to check for the negative of a variable?</p>
  
  <p>Here are my variables:</p>
  
  <pre><code>var frameWidth = 400;
  var imageWidth = parseInt($('#' + divId).find('#inner-image').css('width'), 10);
  var imageMargin = parseInt($('#' + divId).find('#inner-image').css('margin-left'), 10);
  var numberOfFrames = imageWidth/frameWidth;
  </code></pre>
  
  <p>I want to perform a check kind of like this:</p>
  
  <pre><code>if (imageMargin == -numberOfFrames*frameWidth-400 )
  </code></pre>
  
  <p>But I don't know how.</p>
  
  <p>In other words, if numberOfFrames*frameWidth-400 equals 800, I need it to return -800.</p>
  
  <p>Thanks again for any direction you can provide.</p>