Here are some references that should help you out.

Also created a sample jsfiddle to help you start out.


xAxis: {
    type: "datetime",
    dateTimeLabelFormats: {
        day: '%m-%d'   
    tickInterval: 24 * 3600 * 1000,
    min: Date.UTC(<?php echo $date_from;?>),
    max: Date.UTC(<?php echo $date_to;?>)

Basically, what this does is set the type of xAxis to 'datetime' so the tickInterval understands that's it is incrementing by 86400000 milliseconds, and also set the format of the xAxis based on the required date format.
Then the $date_from and $date_to should look like this from PHP handling the form submission.

$date_from = date("Y, m, d",strtotime($_POST['from']) - 2*86400);
$date_to = date("Y, m, d",strtotime($_POST['to']) + 2*86400);

Related Query

More Query from same tag