Disabling Spellcheck in Textarea ElementsSaturday, December 4, 2010·Share·Comments
To disable spell checking on HTML elements in newer browsers (eg. Firefox 3.6) set the attribute spellcheck="false" in the element's opening tag. Note: Some browsers (eg. Safari 5) will not show the red underline for mispelled words until you focus your cursor on a word and then remove it.
For more detailed information refer to the W3C Specification.