Way to get monitor information like size when running exp online?

[wakecarter]

I assume that psychoJS.window.size returns the resolution in pixels. Is that what you wanted? If not then you probably need to write a “resize a rectangle so it’s the same size as a credit card” technique described elsewhere:

Consistent image size across screens

It is actually possible to ask participants for the screen dimensions. The standard procedure is to ask them to resize a rectangle on the screen until it is the same size as an object we know the dimensions of (eg. credit card). jsPsych has a built-in plugin for this: https://www.jspsych.org/plugins/jspsych-resize/ Psychopy could implement a helper method that does the same