Flash of incorrect styling/unmasked password character when hide-on-input is on

[jamesallardice]

When the polyfill runs in "hide-on-input" mode (rather than "hide-on-focus") there is a flash of placeholder-styled text when you type the first character into the input.

This is more of a problem with password inputs, since the flash renders the first password character in plain text, rather than masking it (since the mask won't be applied until keyup).

Currently, this is not a trivial fix, but I hope to get a patch in a future version.