title: What's the best way to calculate date difference in Javascript
body: <p>I doing a function in Javascript like the VisualBasic DateDiff.</p>
  
  <p>You give two dates and the returning time interval (Seconds, Minutes, Days, etc...)</p>
  
  <pre><code>DateDiff(ByVal Interval As Microsoft.VisualBasic.DateInterval, _
    ByVal Date1 As Date, ByVal Date2 As Date) as Long
  </code></pre>
  
  <p>So what's the best way to calculate the difference of Javascript Dates?</p>