Form validation script required

We require a custom stand alone form validation script that validates a form entry and adheres to best usability practices. The script will be used as a standard across all our websites and will be integrated into all our websites moving forward. The form requires client side validation so it checked and validates the form fields as the user completes a field and moves to the next, if they have entered it incorrectly or missed a field then a red cross icon is displayed at the end of the field, the field is also highlighted red. When the form field or cross is rolled over a tool tip message pops up to tell the user what information is required. When the user enters the correct information a green tick appears to indicate that the field has been filled in correctly. If the user hits submit without all information correctly entered. The page needs to anchor link to the top of the form where an error message is displayed and the validation icons appear. The validation needs to work when JavaScript is turned off, via server side validation. And should only appear if the user submits the form with errors and will display an error message and icon next to the form fields, The pop up messages will not appear. Please see visuals attached and more detailed specification document. thanks