SpellCheckAsYouType (SCAYT)

SCAYT allows the user to see and correct misspellings while typing. Misspelled words are underlined. User just needs to right-click a marked word and select a suggestion to replace the word with.

SCAYT for editable controls

This is simple document with two editable controls

You can use contenteditable div element, like this:
This is an exampl of a sentence with two mispelled words. Just type text with misspelling to see how it works.
Or You can use contenteditable iframe element, like this:
Installation Guide

1. Add element script with src="http://example.com/spellcheck/lf/scayt/loader_ui.js" on the page

2. Add attribute sc_dojoType="scayt.ui" to the div element

3. Add attribute sc_dojoType="scayt.ui" to the iframe element

Sample