title: Scope inside constructor
body: <p>I have an instance of a constructor called SlideShow and I wanted to know what the scope of a variable with the key word var would be.
  I understand this refers to the object itself but not sure what scope the itemWidth would be. I presume its local to the function but if the function is global does this mean the var inside it is too? can var itemWidth be accessed from anywhere else?</p>
  
  <pre><code>function SlideShow( width, height ){
    this.width = width;
    this.height = height;
    var itemWidth = 400;  
  }
  </code></pre>
  
  <p>I presume the var inside the update method with is part of the objects prototype object would be local to that function and not global.</p>
  
  <pre><code>SlideShow.prototype.update = function( dir ){
          var dir = value;
  }
  </code></pre>