1. Step one — Add a new bookmark

    1. Tap the + icon.
    2. Tap Add Bookmark.
    3. Tap Save.
  2. Step two — Copy the JavaScript code

    1. Tap inside the text box.
    2. Tap and hold until the magnifying glass appears, then release. A menu containing Select, Select All and Paste will appear.
    3. Tap Select All from the menu. A Cut, Copy, Paste menu will appear.
    4. Tap Copy.
    5. Tap the Done button.
  3. Step three — Replace the original bookmark with JavaScript

    1. Tap the Bookmarks icon.
    2. Tap Edit. Now tap the bookmark you created in Step 1.
    3. Tap its URL (the second field).
    4. Tap the to clear it.
    5. Tap and hold until the magnifying glass appears, then release.
    6. Tap Paste from the menu.
    7. Tap the Done button.
  4. Step four — Installation complete

    Congratulations! ⌘+F should now be installed.

    I'm sorry for the lengthy and complex installation — as soon as this can be made simpler, it will be!