title: What does "i = +i" mean in Javascript?
body: <p>In jquery source:</p>
  
  <pre><code>eq: function( i ) {
      i = +i;
      return i === -1 ?
          this.slice( i ) :
          this.slice( i, i + 1 );
  },
  </code></pre>
  
  <p>Is it used for make sure parse i to int?</p>