The fValidator is an open source (free) unobtrusive javascript tool for easy handling of form validation.

Here's a brief list of the most important features:

• Works perfect with iMask as it's complement.
• Multiple forms per page supported.
• Number of verified fields is not limited.
• Number of filters per field is not limited.
• Predefined formats: required, alpha, alphanum, integer, real, date, email, phone, url. (all customizable)
• Support to register missing formats.
• Highlight fields onValid and onInvalid.
• Error reporting just after onBlur.
• Easy to set and maintain.
• Unobstrutive and XHTML Strict friendly.

fValidator is fully configurable. You can change any default option just initializating the class with an object in JSON. The following options are available:

• (string) msgContainerTag (default "div")
• (string) msgClass (default "fValidator-msg")
• (object) styleNeutral (default {"background-color": "#ffc", "border-color": "#cc0"})
• (object) styleInvalid (default {"background-color": "#fcc", "border-color": "#c00"})
• (object) styleValid (default {"background-color": "#cfc", "border-color": "#0c0"})
• (function) onValid (default Class.empty)
• (function) onInvalid (default Class.empty)
• (object) fValidate[x], x ∈ X := {"required","alpha","alphanum","integer","real","date","email","phone","url"}
  • (string) type - any element of the above X set
  • (regexp) re - regular expression attached to the type
  • (string) msg - message attached to the invalid re match

More Information on how to use fValidator