@ankitdixit,
jQuery is a lightweight and feature-rich JavaScript library. With jQuery, you can achieve the same functionality with fewer lines of code compared to JavaScript. Also, jQuery has inbuilt feature of cross-browser compatibility whereas JavaScript requires extra coding to make it cross-browser compatible. To sum it up jQuery is more user-friendly compared to JavaScript.
Also, if you want to integrate CanvasJS the jQuery way you can use the CanvasJS jQuery plugin. Please check this documentation page for more information on the same.
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Indranil Deo
Team CanvasJS