Fixing Kiwibank’s Account Number Fields

In Kiwibank’s online banking the Account Number is split into four fields. To copy an account number you have to either copy and past in sections, or type it out. I do this a couple of times per week whenever I pay someone new. After months of mild irritation I wrote a Chrome extension to automatically change the 4 fields into one field which strips out hyphens and whitespace and reinserts the number into the original 4 fields. It then shows the number in the original fields so I can check it’s correct.
I’m sure Kiwibank have their reasons but I think it’s safer this way. Copy/pasting the whole number is far less error prone than typing out the number, and I still get to review the number in it’s correct format to make sure it copied correctly.
I’m not publishing the Chrome extension, but the javascript is here: https://gist.github.com/1247125.