What does HackerNews think of devtools-detect?
Detect if DevTools is open and its orientation
https://github.com/sindresorhus/devtools-detect
EDIT: doesn't seem to work if I have devtools as a separate window
There are many ways to detect it's open (eg. https://github.com/sindresorhus/devtools-detect) and it's also possible to mess with it without knowing it's open. A method that's wildly used is firing the debugger break command many times a second, along with other stuff that makes using the tools nearly impossible (slows the browser down to a halt)
https://github.com/nneonneo/steam-phishing-analysis
It's fairly simple code, in the end. The phishers copied the legitimate trading site, as well as the Steam Community login page, and then added some JavaScript code to both as well as tweaking the HTML a bit. In total, three snippets of JS were added: the first detects debuggers using https://github.com/sindresorhus/devtools-detect (the bit that the original blog poster found), the second pops open the fake browser chrome and sticks the fake login page inside an iframe, and the third (running in the iframe) harvests credentials off the copied Steam login page.
Another variant: https://stackoverflow.com/questions/7798748/find-out-whether...