With iOS4.2, Apple added a new feature to enable words to be found in a web page whilst using the Safari browser.
All you have to do is enter the search string in the Safari Search box (where it says Google, Bing, or Yahoo!) and when the list of search suggestions appears you will also see a list of matches on the page you are viewing. The detailed guide below will show you how this feature works.
Open Safari on the iPad and visit a web page, then tap on the Search box (where it says Google, Bing, or Yahoo!) and enter the string of text you are looking for.
A list of search terms will appear, with the list being split in two. The top list will offer suggestions for the selected search engine, Google, Yahoo or Bing. Below this is an area with the heading ‘On This Page ( # matches)'. You do not need to have any matches to the string entered. Tap on Find “search term” in the On This Page section to find the first occurrence of the word in the viewed web page.

When the search term is found on the page, Safari will highlight and zoom in to the word found on the page. At the bottom of the page a results bar will appear with the options of ‘Next’, the number of matches, a search box and ‘Done’.

This bar will be used to continue searching the page. To navigate to the next matching word found in the document tap ‘Next’. If you wish to change the word you are looking for tap on the search box and the keyboard will appear. Enter the new search term and the iPad will automatically find the first occurrence of the new word.
When you are done searching the page tap ‘Done’.
Note: The search bar will only appear when you start a search from the Safari Search box.