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HTML jQuery Basics (2014) Creating a Simple Drawing Application Preparation


I have asked this question to Andrew--the JQuery instructor. If I get his answer, I will post it here.

In the JQuery's simple drawing app, this line of code: var context = $canvas.getContext("2d"); always complaints that getContext is not defined.

Even I used jquery 2.1.1., the problem still exists. If I comment out this line of code, then it compiles.

Any idea?

(from Andrew) If you do $canvas[0] rather than $canvas that should do it. :) [0] grabs he plain old JavaScript representation of the canvas so you can draw context.

2 Answers

Hi Daniel,

$canvas is a jQuery object, not the actual canvas element. Accessing the 1st element (index 0) of this jQuery object will get you the canvas element


I'm not sure if this was omitted from the video but it seems to be in the downloadable project files.

var context = $canvas[0].getContext("2d");

That's why. Thanks for your clear explanation.

You're welcome.