You can even set up an autocommand to auto enable pass through mode for specific websites and disable it when you move away from the page.
au LocationChange .* js modes.passAllKeys = /mail.google\.com/.test(buffer.URL) | /google\.com\/reader/.test(buffer.URL)
that created an autocommand based on the LocationChange event which is run against all websites and then it sets the modes.passAllKeys property to true if the url of the buffer matches that of the regex.
that created an autocommand based on the LocationChange event which is run against all websites and then it sets the modes.passAllKeys property to true if the url of the buffer matches that of the regex.