You can search all text on the current webpage in Safari for iOS. Simply type your term in the Smart Location Bar, do not tap Return, and scroll to the bottom of the list of search suggestions, bookmarks, and history.
If your term is found on the page, you can tap it at the bottom of that results list to show the page and a search bar with tools to quickly move between each instance of your search term.
This is really useful in all sorts of ways, especially when doing just about any kind of research. For example, instead of skimming a long product page to find information about its battery life, I just type “battery” and use this to snap to the first instance of that word on the page. Also: Wikipedia.