Alternatively, if you're using an AMD loader for JavaScript modules, that is also supported in the Chart.js core. Please note: the library will still occupy a global variable of `Chart`, even if it detects `define` and `define.amd`. If this is a problem, you can call `noConflict` to restore the global Chart variable to it's previous owner.
// Chart.noConflict restores the Chart global variable to it's previous owner
// The function returns what was previously Chart, allowing you to reassign.
var Chartjs = Chart.noConflict();
});
```
You can also grab Chart.js using bower:
```bash
bower install chartjs --save
```
###Creating a chart
To create a chart, we need to instantiate the `Chart` class. To do this, we need to pass in the 2d context of where we want to draw the chart. Here's an example.
// Get the context of the canvas element we want to select
var ctx = document.getElementById("myChart").getContext("2d");
var myNewChart = new Chart(ctx).PolarArea(data);
```
We can also get the context of our canvas with jQuery. To do this, we need to get the DOM node out of the jQuery collection, and call the `getContext("2d")` method on that.
```javascript
// Get context with jQuery - using jQuery's .get() method.
var ctx = $("#myChart").get(0).getContext("2d");
// This will get the first returned node in the jQuery collection.
var myNewChart = new Chart(ctx);
```
After we've instantiated the Chart class on the canvas we want to draw on, Chart.js will handle the scaling for retina displays.
With the Chart class set up, we can go on to create one of the charts Chart.js has available. In the example below, we would be drawing a Polar area chart.
```javascript
new Chart(ctx).PolarArea(data, options);
```
We call a method of the name of the chart we want to create. We pass in the data for that chart type, and the options for that chart as parameters. Chart.js will merge the global defaults with chart type specific defaults, then merge any options passed in as a second argument after data.
###Global chart configuration
This concept was introduced in Chart.js 1.0 to keep configuration DRY, and allow for changing options globally across chart types, avoiding the need to specify options for each instance, or the default for a particular chart type.
```javascript
Chart.defaults.global = {
// Boolean - Whether to animate the chart
animation: true,
// Number - Number of animation steps
animationSteps: 60,
// String - Animation easing effect
animationEasing: "easeOutQuart",
// Boolean - If we should show the scale at all
showScale: true,
// Boolean - If we want to override with a hard coded scale
scaleOverride: false,
// ** Required if scaleOverride is true **
// Number - The number of steps in a hard coded scale
scaleSteps: null,
// Number - The value jump in the hard coded scale
scaleStepWidth: null,
// Number - The scale starting value
scaleStartValue: null,
// String - Colour of the scale line
scaleLineColor: "rgba(0,0,0,.1)",
// Number - Pixel width of the scale line
scaleLineWidth: 1,
// Boolean - Whether to show labels on the scale
scaleShowLabels: true,
// Interpolated JS string - can access value
scaleLabel: "<%=value%>",
// Boolean - Whether the scale should stick to integers, not floats even if drawing space is there
scaleIntegersOnly: true,
// Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
scaleBeginAtZero: false,
// String - Scale label font declaration for the scale label
// Function - Determines whether to execute the customTooltips function instead of drawing the built in tooltips (See [Advanced - External Tooltips](#advanced-usage-custom-tooltips))