Stop DOM Modification is Embebed Mozilla Browser

Hello, I am Micael Gallego:

I am writting an software that inspect the DOM document of the loaded
page. In some situations, the DOM document can change while I am
inspect them. For example, a javascript function that execute some code
in some moment (maybe a timer) and change the DOM page.

I want to stop for a moment any DOM modification, to inspect the loaded
DOM. And later, allow normal behaviour of the browser (executing
javascript, etc....)

has somebody any ideas to do these???

Thanks in advance