Rickshaw Update Graph Realtime Data

getLatestData.js

var seriesData = [ [{ x: 0, y: 40 }, { x: 1, y: 49 }, { x: 2, y: 17 }, { x: 3, y: 42 }] ];
var graph = new Rickshaw.Graph( {
  element: document.getElementById("chart"),
  width: 940,
  height: 250,
  renderer: 'area',
  stroke: true,
  series: [
    {
      color: 'steelblue',
      data: seriesData[0],
      name: 'SMS per minute'
    }
  ]
});			
graph.render();
var getLatestData = function(){
  jQuery.ajax({
    url: "/data.json",
    type: "GET",
    data: {
    campaign_id : <?= $campaignId; ?>,
    most_recent : mostRecent
    },
    dataType: "json",
    success: function(newData, textStatus, jqXHR){
      seriesData[0].push( { x: newData.x, y: newData.y } );
      graph.update();
    }
  });
};

setInterval( function() {
	getLatestData();

}, 60000 );