1.8.4.3 web.form.field.extra -- Extra fields for use with web.form

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1.8.4.3 `web.form.field.extra` -- Extra fields for use with `web.form`

This module provides two classes: `URL` and `Email`. Both these classes behave exactly the same as the `web.form.field.typed.String` class except that they only accept as values strings that are URLs or Emails respectively.

For example:

    >>> import web.form.field.extra as field
    >>> email = field.Email(name='emailField')
    >>> print email.html()
    <input type="text" name="emailField" value=""> <small>eg. james@example.com</small>
    >>> email.value = 'this is not an email address'
    >>> email.valid()
    0
    >>> print email.error()
    Please enter a valid email address. eg. james@example.com
    >>> email.setError('')
    >>> email.value = 'james@example.com'
    >>> email.valid()
    1