How to parse part of html code?

Question

JavaScript

Hello. There is a task using js to parse html code from the generals.mobi domain (you need to parse everything except css and graphics as it will be in cordova)
Ajax is not suitable because there is no permission from the owner.
The client will be used for personal purposes. I do it in order to somehow speed up the robot from the SIM: D

PS

I thought that you can load using a frame, but then the problem is that css is loaded with a frame too.