title: JavaScript Browser vs NodeJs compatibility
body: <p>I cannot get why in <code>Browser</code> code like this:</p>
  <pre class="lang-js prettyprint-override"><code>var gLet = 5;
  alert(window.gLet); // 5 (become a property of the window object)
  </code></pre>
  <p>even thought it is old behavior works differently in Node.js:</p>
  <pre class="lang-js prettyprint-override"><code>var gVar = 5;
  console.log(global.gVar); // undefined (don't become a property of the global object)
  </code></pre>
  <p>But it works like this in Node.js:</p>
  <pre class="lang-js prettyprint-override"><code>gVar = 5;
  console.log(global.gVar); // 5 (become a property of the global object)
  </code></pre>
  <p>This mean that Node.js do not completely support old behavior? Just try to figure out all of it ...</p>