Highcharts (highstock) plotting incorrect date on x-axis line chart

Question

Here I have an example of a highstock chart I have generated: http://jsfiddle.net/9gTN8/

There are 3 data points with dates defined using the Date.UTC method. Despite the last date in the series being 2013-07-15 , the point is plotted in August. Likewise the other points appear to be being plotted a month ahead of where they should be.

I have used ordinal: false to allow for irregular date intervals, which is a feature of highstock.

What is the reason for this and how can I solve it?

Edit:

My date in each datapoint is produced from php like so:

echo "\n[Date.UTC(" . date("Y, m, d", strtotime($date)) . "), " . $value . "]";

I know I could have several php date() functions to decrement the month myself but I'd hope there'd be a more efficient way. Eg is it possible to replicate the javascript Date.UTC method in php and just output the big number (no. of milliseconds since 01/01/1970) straight off?

Answer 1

The solution is to not use Date.UTC and just use php's date format like so:

echo "\n[" . 1000 * date("U", strtotime($date)) . ", " . $value . "]";

This will output the epoch timestamp as defined in the manual in seconds. Times by 1000 to get milliseconds as javaScript requires.