title: JS: What's the difference between =+ and +=
body: <p>given the following block of code</p>
  
  <pre><code>var sumX = 0,
      sumY = 0,
      x = 1,
      y = 2;
  sumX =+ x;
  sumY += y;
  </code></pre>
  
  <p>What is the difference between the two assignment operators?</p>