Use Chrome™ spell checking within all the page.
This extension allows you to check if your web page is correctly spelled by setting all the page editable and thus using the built-in spell checking capabilities of Chrome™.
PS: As a side effect (:P), you can use this app to preview some little text changes in your website.
WARNING: This is a quickly developed app... It is not intended to look good, but to just provide the required functionalities.