html, body, #container {

    width: 100%;

    height: 100%;

    margin: 0;

    padding: 0;

}

anychart.onDocumentReady(function() {

    // create chart

    chart = anychart.surface()

    // set data

    chart.data(generateData(hyperbolicParaboloid));

​

    // configure axes

    chart.zAxis().stroke(null); 

    chart.zAxis().ticks().stroke("1 lightgray");    

    chart.xAxis().labels(false);

    chart.yAxis().labels(false);

    // configure grids

    gridStroke = {color: 'lightgray', thickness: 1, dash: '5 5'};

    chart.xGrid().stroke(gridStroke);

    chart.yGrid().stroke(gridStroke);

    chart.zGrid().stroke(gridStroke);

    // enable box

    chart.box({color: 'lightgray', thickness: 1});

    // display chart

    chart.container('container').draw();

});

// generate a data set from function

var generateData = function(z_function) {

  var max_val = 5;

  var step = 0.5;

  var output = [];

  for (var x = -max_val; x <= max_val; x += step) {

    for (var y = -max_val; y <= max_val; y += step) {

      output.push([x, y, z_function(x, y)]);

    }

  }

  return output;

};

// hyperbolic paraboloid function

var hyperbolicParaboloid = function(x, y) {

  return Math.pow(y,2)-Math.pow(x,2);

};