In the Script.js file u shoud add " qrValue " variable in
< qrImg.src = https://api.qrserver.com/v1/create-qr-code/?size=200x200&data=${}; > at line no. 47
B'coz of this U can generate QR code by passing the value " let qrValue = qrInput.value.trim(); "
U initialized " qrValue " it at line no. 40