Adam, You misunderstood my question

 

What i want is basically, when i switch the editor between normal and html mode, it will not change my code at all

including the space and indentation.

and I dont want any script tag

for e.g, I need to be able to put some code inside the <pre></pre> tag

You can try yourself, pasting some c# code inside pre tag , and when you switch to edit mode for the first time, it works ok
All the indentation still there, however, if you switch to html mode, then edit mode, it will remove all the indentation and space.