[web2py] Mimicking HTML5 pattern attribute for inputs

[RKS]

I'm looking to validate all of my forms with HTML5 and the pattern 
attribute, but as always, nothing is perfect on the internet and I still 
need a backup to catch those users who do not use HTML5 friendly browsers.

I'm having trouble finding exact representations of the regular expressions 
in the handbook so if you know, I'd appreciate some help. I have written 
the code in two ways, the HTML way and the HTML helper way (see below) and 
the HTML5 works and validates in modern browsers except IE as expected but 
I can't translate them to python.

An example, you will see below, is the expression 
pattern="[A-F0-9]{11}|[A-F0-9]{14}"
This effectively forces an input to only contain uppercase letters of A-F 
and numbers 0-9. It also ensures the length is exactly 11 characters or 14. 
So how would I use this in web2py? IS_LENGTH seems to accept only a range 
from my tests and so far I've only found IS_ALPHANUMERIC to control what 
characters are accepted.

Please seem the form below:

HTML:

<form id="activate_form" method="post" action="">
        <label for="meid">MSIE/ESN <sup>*</sup></label>
        <input name="meid" pattern="[A-Fa-f0-9]{11}|[A-Fa-f0-9]{14}" 
placeholder="MEID/ESN" required />
        <br />
        <label for="zip">Zip Code <sup>*</sup></label>
        <input type="number" name="zip" pattern="{5}" placeholder="Zip 
Code" required />
        <br />
        <br />
        <br /><br />
        <input type="button" name="cancel" value="Cancel" 
onClick="history.go(-1);return true;" />
        <input type="submit" name="submit" value="Activate" />
           <p class="small"><sup>*</sup> denotes a required field.
    </form>



HTML Helpers:

form=FORM(LABEL('MEID/ESN 
',(SPAN('*'))),INPUT(_name='meid',_pattern="[A-F0-9]{11}|[A-F0-9]{14}",_placeholder='MEID/ESN',_required='required',_title="The
 
MEID/ESN number only contains 11 or 13 characters, the letters A-F, and the 
numbers 0-9.",requires=[IS_LENGTH(11|14),IS_NOT_EMPTY()], 
_onblur="this.checkValidity();"),BR(),LABEL('ZIP CODE 
',(SPAN('*'))),INPUT(_name='zip',_type='number',_pattern="[0-9]{5}",_placeholder='Zip
 
Code',_required='required',_title="We only required the five character zip 
code.",requires=IS_NOT_EMPTY()),BR(),BR(),BR(),BR(),INPUT(_type='button',_name='cancel',_value='Cancel',_onclick="history.go(-1);return
 
true;"),INPUT(_type='submit',_name='submit',_value='Activate'),_method='post',_id='activate_form')
    if form.accepts(request,session):
        response.flash = 'Form accepted'
     #   redirect(URL('next'))
    elif form.errors:
        response.flash = 'Form has errors'
    return dict(form=form)



Thanks.