You can disable the auto correct/capitilize features on form inputs on the iPhone, so when users visit your site and fill in the forms the iPhone wont try to correct the spelling of you email or silly username.
It’s quite simple to do:
So you just use the autocapitalize and autocorrect properties.
It’s designed for the iPhone and Safari, so I don’t know how far it goes but it’d be a cool feature to see on other browsers and platforms as well.
The example code is from the Apple Developer Library