How to lock to a textbox to accept only numbers?

Two possibilities:

yourTextBox.Inutmask = '9'
yourTextBox.Format = '999999'

See VFP Help for detail and other options for the properties Inputmask and Format.

Try .wcHTML5inputType=‘number’

It didn't work, are there any examples in the live tutorial?

It didn't work

What did you do and obtain? Can you post some illustration?

are there any examples in the live tutorial?

Not for now

It worked correctly, I was using a customization from my web designer before, so it didn't work this for. Thank you.