[peterangular]

You're not handling input elements correctly. Using CSS to hide things like CC number fields etc via blurring is a fool's errand. You're going to have split-second rendering issues that still display info in cleartext on the screen (I get this is for an "already loaded page" but still - I would hope blurring persists from page to page). Sometimes Chromium gets buggy and can display stuff for seconds at a time before a CSS3 blur is drawn (trust me - I've tested this at scale).

As someone who's had to do this for automation purposes (can't get a CC/SSN in a screenshot due to compliance) you first set sensitive fields to "password" on the input element, query the DOM to ensure a "safe state", and THEN you fill then input.

Also - other comments on blurring being reversible are correct as well.

TLDR: Replace attributes/characters to do properly censor text on a webpage. Source - 10+ years of automation (same logic still applies to vanilla front-end dev). Not a very useful tool.