[ChartJS | multiple chartjs in the same page] #ChartJS

demo.html

<div style="width: 50%">
    <canvas id="canvas" height="450" width="600"></canvas>
</div>

<div style="width: 50%">
    <canvas id="canvas2" height="450" width="600"></canvas>
</div>

demo.js

var randomScalingFactor = function(){ return Math.round(Math.random()*100)};

var barChartData = {
    labels : ["January","February","March","April","May","June","July"],
    datasets : [
        {
            fillColor : "rgba(220,220,220,0.5)",
            strokeColor : "rgba(220,220,220,0.8)",
            highlightFill: "rgba(220,220,220,0.75)",
            highlightStroke: "rgba(220,220,220,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        },
        {
            fillColor : "rgba(151,187,205,0.5)",
            strokeColor : "rgba(151,187,205,0.8)",
            highlightFill : "rgba(151,187,205,0.75)",
            highlightStroke : "rgba(151,187,205,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        }
    ]

}
    var barChartData2 = {
    labels : ["January","February","March","April","May","June","July"],
    datasets : [
        {
            fillColor : "rgba(220,220,220,0.5)",
            strokeColor : "rgba(220,220,220,0.8)",
            highlightFill: "rgba(220,220,220,0.75)",
            highlightStroke: "rgba(220,220,220,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        },
        {
            fillColor : "rgba(151,187,205,0.5)",
            strokeColor : "rgba(151,187,205,0.8)",
            highlightFill : "rgba(151,187,205,0.75)",
            highlightStroke : "rgba(151,187,205,1)",
            data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
        }
    ]

}
window.onload = function(){
    var ctx = document.getElementById("canvas").getContext("2d");
    window.myBar = new Chart(ctx).Bar(barChartData, {
        responsive : true
    });
    var ctx2 = document.getElementById("canvas2").getContext("2d");
    window.myBar = new Chart(ctx2).Bar(barChartData2, {
        responsive : true
    });
}