Note that on static webpages without fancy interactive widgets, there's several built-in ways in iOS to increase font size. On most websites, these are all you ever need:
(1) Screen Reader mode: On individual posts/entries of most blogs and news sites, scroll to the top of the page and tap the screen reader icon at the beginning of the address bar to view the body of the page in a format that strips away everything but text and images.
(2) When NOT in screen reader mode, one can usually double tap a column on a multi column page to zoom it to full screen width.
(3) One can usually spread/pinch 2 fingers on the screen to zoom in/zoom out a portion of the page.
(4) Two finger swipe down from the top the screen for text-to-speech. Scroll down beforhand to the part you actually want to listen to so you pdon't have to hear all the headers.
(5) For full function text-to-speech, letting you select different parts of the page to be read aloud, go to the Settings app, go to "General > Accessibility > Voiceover Shortcut" (All the way down at the bottom) and choose "Voiceover" so that triple clicking the home button toggles voiceover mode. (See "General > Accessibility > Voiceover" for a list of Voiceover gestures. If you're vision-impaired, it's worth familiarizing yourself with them.