TypeError: Cannot read property 'concat' of undefined

[wakecarter]

Have you defined event as per my crib sheet or code snippets pages? If not then keys = event.getKeys(); will fail online and keys will be undefined.

Well, JS code errors on Pavlovia

You’ve linked to my code snippets page rather than my crib sheet. However, at the top it says: Code components should be Auto Py->JS unless code has been added to the PsychoJS column. I would recommend that all experiments intended to run online contain a JavaScript code component in their first routine called code_JS with the following in Begin Experiment. thisExp=psychoJS.experiment; win=psychoJS.window; event=psychoJS.eventManager; shuffle = util.shuffle; Array.prototype.append = [].push;…