Hello,

Your ticket was somehow missed and checking now.
Perhaps, it's too late but it may help someonhe.

Solution could be to apply some 3rd party input mask library.

http://www.google.com/search?q=jquery+input+mask

Also check faq: How to mask a field, for example like this: (NN) NNNN-NNNN ? N stands for number.

How-Tos & FAQs

My interest isn't to mask an input field but on the possibility to block the focus in in that field in which have been inserted erroneous values instead of highlight the error in the add or edit dialog.
Regards

What one can do is to validate field using JS function on blur event of field.
And if it is incorrect, reset it's focus on that field.

http://hastebin.com/acurobasaw.php
Refer line 62 and 127.

Good, very good.
Thank you very much, Abu
Regards