Using JavaScript to run a sketch on an html processing.js

edited March 2017 in JavaScript Mode


I wrote a very basic html document and am trying to use JavaScript to dynamically add the elements that would run a Processing sketch with processing.js.

I'm adding a script element that points to processing.js, and adding it to the document's head. Then I'm creating a canvas that points to my sketch, and adding it to a div in the body. They seem to be added in the dom ok when I check inspect from a browser, but the sketch doesn't run. If I directly write those 2 elements inside the document, then it works fine, so I'm not sure if something's not evaluating, or evaluating out of order, and so on.

I should note that I am running this on a local server. I was able to get this to work easily with p5.js, but hoping I can get it for processing.js too because most of my 3d sketches uses it! I broke it down to a simple example so you can check my code below.

<html lang="en-US">
        <!-- Works if I uncomment this!
        <script type="text/javascript" src="resources/libs/processing.js"></script>

        <div id="sketchContainer">
            <!-- Works if I uncomment this!
            <canvas data-processing-sources="js/header_sketches/my_awesome_sketch.js"></canvas>

            var scrElt = document.createElement("script");
            scrElt.type = "text/javascript";
            scrElt.src = "resources/libs/processing.js";
            scrElt.async = false;

            scrElt.onload = function() {
                var canvas = document.createElement("canvas");
                canvas.setAttribute("data-processing-sources", "js/header_sketches/my_awesome_sketch.js");



  • edited March 2017

    Hmm... Still not good w/ DOM stuff. But my hunch is that right after "processing.js" is loaded & executed, it searches for some <canvas> w/ data-processing-sources attribute on it.
    If none's found at that time, nothing happens! :|

    Seems like you only create your <canvas> onLoad(). Maybe it's too l8 for that then? :-??

  • edited March 2017

    Just did a test but creating canvas before still doesn't seem to work. But if I hardcode processing.js to be in there then have JavaScript create the canvas it works. I think that's why I was trying to use onLoad() in the first place. Just can't seem to get both of them working in pure JavaScript!

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