@ Dong
I remember you made a thread about Wikia showing pop-up and I told you about screenshot. There is a method I just found that saves an entire page as PDF not only what is on your screen.
You need to be on Chrome browser to do this.
1. Go to the web page you want to see
2. Click the tree dot button and choose print
3. Click "Change" and choose save as PDF.
Now you can view a page offline.
I haven't tested it on mobile because I don't use Chrome on mobile, but if you have PDF viewer on your phone, I think you can do the same.