[njhelloworld]

I am really new to canvasjs I need to create a running line chart based on data from database. What I did is something like this, error comes like Uncaught ReferenceError: $ is not defined at window.onload (livechart.php:7). Always shows.. Please help me with this..Thank you so much for any reply

window.onload = function () {
        $.getJSON("www.website.com/livedata.php", function(result){
        var dps = []; // dataPoints
        var chart = new CanvasJS.Chart("chartContainer",{
            zoomEnabled:true,
            panEnabled:true,
            animationEnabled:true,
            title :{
                text: "Analysis for Soil Ph",
                fontSize: 20
            },          
            data: [{
                type: "line",
                dataPoints: dps 
            }]
        });
        var xVal = 0;
        var yVal = 100; 
        var updateInterval = 100;
        var dataLength = 500; // number of dataPoints visible at any point
       var updateChart = function (count) {
            count = count || 1;     
            for (var j = 0; j < count; j++) {   
                yVal = yVal +  Math.round(5 + Math.random() *(-5-5));
                dps.push({
                    x: xVal,
                    y: yVal
                });
                xVal++;
            };
            if (dps.length > dataLength)
            {
                dps.shift();                
            }
            
            chart.render();     

        };
        updateChart(dataLength); 
        setInterval(function(){updateChart()}, updateInterval); 

});
    }