Is it possible to permanently disable CSS on Android browsers like Firefox, Dolphin, Chrome and Opera?
I want the browsers to completely ignore any stylesheet rule.
Can this be achieved with the help of AdBlock Plus?
I have to suggestions that are probably going to be about as close as you're going to get to removing the 'styles' from websites. They're there for a reason, like previously mentioned, and removing them is very close to disabling the HTML but not entirely the same as you're stil left with the paragraphs and links (the core content of the site, just without the look and formatting).
The first suggestion will replace (not remove) a lot of the CSS from the pages. The add-on is called Stylish, just do a search for it in Firefox Mobile, and then go to 'Menu' -> 'Tools' -> 'Add-Ons', tap the Stylish add-on, and then the 'manage styles' button. When the page opens there's a link that you can click on that will direct you to a page that has a ton of 'styles', which will let you change the whole look of either one, several, or all web pages.
The second suggestion is to use an app like Pocket (which is what I currently use and love) that will let you easily save a page from nearly any browser (using an add-on) into your 'Pocket' and then view it as an article (with the CSS/styles completely removed from the content). Another major benifit of Pocket is you can configure the settings in the app to store all of the pages offline so you can access them even without an internet connection (extremely useful for tablets that don't have mobile data).
I know these suggestions aren't exactly what you were looking for but I'm hoping that between the two you'll be able to accomplish what you are trying to. I did search the web for a few minutes and didn't find a way to completely disable the style sheets in any mobile browser or I would have posted my findings.
Note: You can completely disable the styles on a PC (and probably a Mac) by using the Web Developer plugin, there's a Chrome version as well but I can't provide the link because I don't have the 'reputation' on stackexchange yet. After you install the plugin, you can quickly disable them using the shortcut key combo
Alt + Shft + A or by clicking the CSS menu button and navigating to
CSS > Disable Styles > Disable All Styles. Hope this helps!