title: Difference between 'var a = b' and 'this.a = b'
body: <p>I have been dealing and learning about Objects and OOP in JS in the past few days and I good a basic understanding how they work now.</p>
  
  <p>One thing that bothers me, and I have problems with to understand, is where is the difference between this:</p>
  
  <pre><code>var bird = "Birdy: var bird"
  </code></pre>
  
  <p>and this</p>
  
  <pre><code>this.bird = "Birdy: this.bird"
  </code></pre>
  
  <p>Both of them will add a property(<em>bird</em>) to the object. In this case <em>this</em> points to the <em>object Window</em>. Where is the difference? Why are people using the *this.*bird method? What are the advantages of it(could someone show me an <strong>example</strong> where <em>this.bird</em> is superior to <em>var bird</em>)?</p>
  
  <p>Let´s take this <a href="http://www.lessmilk.com/tutorial/2d-platformer-phaser" rel="nofollow noreferrer">tutorial</a> for example: why is he using <em>this</em> there? Isnt <em>this</em> redundant? Couldnt this entire thing be done removing the <em>this</em> and/or replacing it?</p>