Proper way to remove all series data from a highcharts chart?

The following way the chart will not redraw every iteration.
So you'll get a better performance.

while( chart.series.length > 0 ) {
    chart.series[0].remove( false );
}

chart.redraw();

Another way to remove all series in HighCharts with a for loop is to start from the end. Here's how to do it:

var seriesLength = chart.series.length;
for(var i = seriesLength - 1; i > -1; i--) {
    chart.series[i].remove();
}

I prefer to go this route because when using a HighStock chart, the navigator is usually the first series. I also prefer to keep a variable set to the navigator series. In that case, I'll do the following:

var seriesLength = chart.series.length;
var navigator;
for(var i = seriesLength - 1; i > -1; i--) {
    if(chart.series[i].name.toLowerCase() == 'navigator') {
        navigator = chart.series[i];
    } else {
        chart.series[i].remove();
    }
}

Now I can easily set the navigator series.

Here's an example of removing all series from a Highchart: http://jsfiddle.net/engemasa/srZU2/

Here's an example of resetting a HighStock chart with new data (including the navigator series): http://jsfiddle.net/engemasa/WcLQc/

try this to remove all chart series,

while(chart.series.length > 0)
    chart.series[0].remove(true);

it works for me. the code

for (var i = 0; i < chart.series.length; i++)

won't work because the chart.series.length is decreased each time remove() is called. That way, the i will never reach the expected length. Hope this helps.