Viewing source on a mobile device

How do you view source on a mobile phone web page (Source being the HTML code)?

I've found a few places online that have suggested ways, but none of them have worked to this point. I'm looking to do this on a Windows Phone 8.1 and an old Android phone.

Thanks!

can you try and install operamini browser and use paste or type server:source to the url bar and it will view the source of the page you are currently on. Hope this help?