Web page entry fields causing safari to freeze

using a macbook air and mavericks came pre-installed. Safari and chrome both freeze when i try to input information for sign-ups etc. and i have to do a force quit

have tried previously mentioned options for disabling all extensions, clearing cache and enabling develop menu allowing JavaScript from smart search field.

Still same problem its happening every time i try to input information in entry fields on any website.

any advice or suggestions most welcome