WordPress is formatting my HTML Tags

Did you uncheck “WordPress should correct invalidly nested XHTML automatically” under “Settings” – “Writing”?

I have that unchecked and I have a similar problem as the OP.

Yeah that was unchecked already

when i switch between the visual and html editor the code remains the same, its only when i click save that it removes everything

well as a temporary solution i found this

https://www.randomsnippets.com/2008/03/07/how-to-find-and-replace-text-dynamically-via-javascript/

It will find and replace strings for you.

I simply changed the code to look for class="new_window" and added that to my links.

But not permanent