[Solved]-Highcharts Single Line series JSON date data format-Highcharts

In PHP do this:

 $timestamp =  1000 * strtotime($your_date);

There is a javascript function Date.UTC which will do the conversion for you. e.g.

[Date.UTC(2013,0,1),55],

Note, the Javascript months start at 0 (for Jan), not 1.

N.B. Make sure your axis type is 'datetime'.