HTML DOM Editing on iPhone?

i'm trying to find of either a tweak, app, or browser that will let me go to a website, like facebook for example, and edit what is shown on the page. The same way you would on a windows computer by pressing F12 and editing the DOM Elements.

I found a tweak call WebSource on cydia, but it doesn't seem to work with ios 8 as it just freezes the browser.

Does anyone know of anything that would work? I have an iPhone 6 on iOS 8.1

not wanting to have the plug my phone into my computer either as that was another one i have found

i also noticed that safari now has some extensions for it in ios8 and wondering if maybe there were an extension to allow me to edit the elements?