Remove/Change specific Html tags NotePad++

Use notepad++ with regular expressions

1. Open Notepadd++
2. Press CTRL+H
3. Select Regular expression as search mode
4. Enter ^.*myClass.*$ under Find what and nothing under Replace with
5. Click Replace all

Cases where start and end strings are in different lines (Notepad 6.xx)

We use a workaround and temporary delete all carriage returns (+newlines).
This gives us a single long line where its much easier to use RegEx. Later we put the carriage returns back.

1. Choose a unique string like %%%NEWLINE%%% which doesn't occur so far in your text.
   Test it first with a simple CTRL+F search
2. Press CTRL+H and select Regular expression as search mode
3. Find \r\n and replace with %%%NEWLINE%%%. Click Replace all.
   \r\n are special characters and stand for carriage return and newline. You get one long line.
   Remember: From now on you can't use ^ and $ anymore
4. Find <div .*?myClass.*?</div> and replace with nothing (Notice the space)
5. Find %%%NEWLINE%%% and replace with \r\n to bring back our normal text structure

While writing my edit I noticed you have changed your question with a game breaker. This method (probably no RegEx method at all) won't work while you have nested <div></div> tags. The RegEx engine can't know if it should stop at the 2nd, 3th or n-th </div>

Used RegEx

^  → line beginning
.  → any single character
*  → repeat previous pattern 
.*  → any characters as long as possible (greedy)  
.*? → any characters as short as possible (non greedy)
$  → line end

Used resources

• http://markantoniou.blogspot.de/2008/06/notepad-how-to-use-regular-expressions.html
• http://www.scintilla.org/ScintillaDoc.html#Searching
• https://stackoverflow.com/questions/4398613/notepad-newline-in-regex