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I am trying to use chartsjs to make a pie chart. I have followed the steps in the chartjs documentation and I have included chart.js and the canvas element. i added the script that should create the chart as the example provided in the chartjs documentation. I am getting the following error: Uncaught TypeError: Cannot read property 'canvas' of undefined Does anywhone know how to fix this? What am I doing wrong? Thanx in advance!
HERE IS THE CODE:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="<?php echo base_url(); ?>media/js/chart.js"></script>
<script type="text/javascript" src="<?php echo base_url(); ?>media/js/jquery.js"></script>
</head>
<canvas id="myChart" width="400" height="400"></canvas>
<script type="text/javascript">
$(function() {
options = {
//Boolean - Show a backdrop to the scale label
scaleShowLabelBackdrop: true,
//String - The colour of the label backdrop
scaleBackdropColor: "rgba(255,255,255,0.75)",
// Boolean - Whether the scale should begin at zero
scaleBeginAtZero: true,
//Number - The backdrop padding above & below the label in pixels
scaleBackdropPaddingY: 2,
//Number - The backdrop padding to the side of the label in pixels
scaleBackdropPaddingX: 2,
//Boolean - Show line for each value in the scale
scaleShowLine: true,
//Boolean - Stroke a line around each segment in the chart
segmentShowStroke: true,
//String - The colour of the stroke on each segement.
segmentStrokeColor: "#fff",
//Number - The width of the stroke value in pixels
segmentStrokeWidth: 2,
//Number - Amount of animation steps
animationSteps: 100,
//String - Animation easing effect.
animationEasing: "easeOutBounce",
//Boolean - Whether to animate the rotation of the chart
animateRotate: true,
//Boolean - Whether to animate scaling the chart from the centre
animateScale: false,
//String - A legend template
legendTemplate: "<ul class=\"<%=name.toLowerCase()%>-legend\"><% for (var i=0; i<segments.length; i++){%><li><span style=\"background-color:<%=segments[i].fillColor%>\"></span><%if(segments[i].label){%><%=segments[i].label%><%}%></li><%}%></ul>"
};
data = [
{
value: 300,
color: "#F7464A",
highlight: "#FF5A5E",
label: "Red"
},
{
value: 50,
color: "#46BFBD",
highlight: "#5AD3D1",
label: "Green"
},
{
value: 100,
color: "#FDB45C",
highlight: "#FFC870",
label: "Yellow"
}
];
ctx = $("#myChart").get(0).getContext("2d");
myNewChart = new Chart(ctx[0]).Pie(data, options);
});
</script>
</html>
317
The problem lies on this line here:
myNewChart = new Chart(ctx[0]).Pie(data, options);
And in specifically ctx[0]. When you defined ctx here:
ctx = $("#myChart").get(0).getContext("2d");
ctx is an object called CanvasRenderingContext2D, which haves properties. You are trying to treat it as an Array when it's not. ctx[0] is therefore undefined. So the solution is actually simple, as you have found out.
Change ctx[0] to ctx, and you have your nice animated pie chart.
ctx = $("#myChart").get(0).getContext("2d");
myNewChart = new Chart(ctx).Pie(data, options);
Fiddle Here
125
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