There exist many websites and web applications with elements of poor usability, engineering, design and so on. Some exhibit features so poor I can only attribute them to laziness. Some actually make me feel offended that I have to jump through hoops to accommodate their laziness. Top of my list are form fields for postcodes, phone numbers, dates, times or any similar type of data. Simple numeric data. Easily validated and normalized. Yet I often see requirements to enter the data in a very specific format, often at odds with how humans customarily write such data. To most people (who are not developers) it can be very confusing to enter data in a perfectly normal way and have a computer tell them it is invalid. For me it is offensive since I know it is practically always the result of data not being normalized. A developer that does not normalize input data before validating it can only be described as lazy or, if you prefer, incompetent.
Nothing can be simpler, right. In many countries it is simply a few digits. Some through a few alphabetic characters in there. I'll focus on local Swedish websites and Swedish postcodes. We have 5 digit postcodes. They are typically written "123 45". So Why would any Swedish website validate that input and claim it is invalid. As a developer I know it is probably that a space is not a numeric character and that adding it also make the string 6 characters long and not 5.
A phone number is a string of numeric characters. Anything else: spaces, parenthesis, dashes and other chrome, is just that: chrome. None of that is part of the data. No server at ATT, Telia, Vodafone or any other network carrier reads these thing and need them in order to route a call. Quite the opposite. Any phone network and particularly cellular networks require a very specific internationally standardized format. Guess what? It is all numeric. A Swedish cellphone might be typed "0701 - 23 45 67" in my address book but the phone sends 46701234567 to the network anytime I make a call.
Dates and Times
These are a bit more complex than the above. But the same principles apply. Then again, most web-focused programming languages have functions to parse a myriad of ways one could type a date or time and create a proper date or time object or data type. If you still find it does not work for you then, in this case, you should provide something other than a blank test field. Try googling for datepicker or timepicker. The problem will be one of choosing your favorite rather than finding anything at all.
I have ranted a bit now so I thought I'd put my code where my mouth is. Since I am not allowed to share my phone number normalizer code I wrote at work I thought I'd at least share the secret to all the normalizing tasks above... It's regex. Regular Expressions.
Getting rid of whitespace
The following will "match" whitespace characters. By substituting the matches with nothing you will simply remove all whitespace from a string. /\s/
Remove anything that is not a number
And the following will remove non digits if you substitute the matches with nothing. /\D/
A very very very simple example in Ruby
num = "(0)701 - 23 45 67".gsub(/\D/,'')
Seriously. That is all it takes to turn an offensive web form into a more humane one.