If you use WhatsApp web a lot like some of us do, then you know the fears of posting a message to the wrong person or group. This little script once injected into the whatsapp web page will prompt you before you send a message.
It works by simply noting each time you change the recipient of a message by highlighting them on the left panel. Once you've confirmed the first time, it won't prompt you again until you click another user or group.
A simple script that will prompt you before you send a message to someone on Whatsapp Web.
NOTe: This script only works on Chrome, at the moment, not tested on FireFox, Edge etc
For this to work we'll need an extension that can inject script into a web page. I prefer to use Styler, this can be installed from this link
https://chrome.google.com/webstore/detail/styler/bogdgcfoocbajfkjjolkmcdcnnellpkb?hl=en
Once installed, simply copy paste the script into the Javascript/JQuery textbox in Styler while viewing the web.whatsapp.com tab then refresh the page.