Attempting to sign will not produce anything visible (other than a little start dot) -- but if you change the export as drop down to SVG you will see that the signature is being captured. This only seems to happen in Chrome -- that is, the issue does not occur when using firefox, opera or native android browser on the same device.
The signature does not render (although it is being captured) on Galaxy devices (tablets, phones, etc) running Chrome as the browser.
To replicate... visit the following demo page from willow using a galaxy device and Chrome browser.
http://willowsystems.github.io/jSignature/#/demo/
Attempting to sign will not produce anything visible (other than a little start dot) -- but if you change the export as drop down to SVG you will see that the signature is being captured. This only seems to happen in Chrome -- that is, the issue does not occur when using firefox, opera or native android browser on the same device.