I’ve seen folks use the Google Charts API for this, which might be easier to get going. The format is:
<img src='/uploads/db2156/original/2X/7/7cec6b395d90fd00a7fe1c610968de76bc623c9a.png'>
Which creates:
So you could run:
document.getElementById("qrcode").src="https://chart.googleapis.com/chart?cht=qr&chl=Hello+Chris&choe=UTF-8&chs=100x100";
A bit more documentation here: https://developers.google.com/chart/infographics/docs/qr_codes