There actually is a search text feature, it's just not that easy to find. Type the text into the url bar, and then scroll down all the way to the bottom after the auto complete suggestions and it will let you view matches on the page. (really shitty location for it)

Well, Firefox on iOS still uses the same webkit engine Safari does.

Also, Safari doesn't [lack search text function](http://cdn.osxdaily.com/wp-content/uploads/2013/10/find-text...).

Safari does include a search text function. Tap on the search bar and type in your text. Don't hit enter, scroll down to the autosuggest results and it says find on page. Tap that.