JavaScript NaN Error in IE but not in Firefox, Chrome etc
<p>I've got a page where two dates are selected and the inclusive difference between them is displayed in a third text input.</p>

<p>The calculation is made nicely in Firefox, Chrome etc but IE6, IE7 &amp; IE8 a NaN error is displayed.</p>

<p>I've tried parseInt(), number() etc but to no avail.</p>

<p>It's all being temporarily held at <a href="http://www.thewebdes.co.uk/dev/hol/" rel="nofollow">http://www.thewebdes.co.uk/dev/hol/</a> and there's a .rar file so all code is downloadable if you wish to help. I'm hoping it's a simple one to people who are good with JavaScript!</p>

<p>--- edit ---</p>

<p>Sorry guys,</p>

<pre><code>$('#firstday, #lastday').datepicker({
    showOn: 'both',
    buttonImage: 'img/cal.gif',
    dateFormat: 'dd/mm/yy',
    onSelect: function(){
      // Date will give time difference in miliseconds, divide with 1000*60*60*24
      var firstday = new Date($("#firstday").val().split("/").reverse().join(","));
      var lastday = new Date($("#lastday").val().split("/").reverse().join(","));
      // Remove weekend days from count
      var weekend_count = 0;
      for (i = firstday.valueOf(); i &lt;= lastday.valueOf(); i+= 86400000) {
        var temp = new Date(i);
        if (temp.getDay() == 0 || temp.getDay() == 6) {
          weekend_count++;
        }
      }
      var totaldays = ((lastday - firstday) / 86400000) + 1 - weekend_count;
      $('#totaldays').val(parseInt(totaldays)); // parseInt as sometimes, with a long gap between first and last, a decimal number is displayed. Ok, people wont be booking 120 day holidays, but it keeps things proper
    }
  });
</code></pre>
