I have a numeric input box, as part of a form. I'm implementing delimited splitting, to make large numbers easier to read. ie, 1000000 would become 1,000,000.
Would it be a good idea to automatically update the input with commas as the number is typed? So that typing 1,000,000 would show:
1 10 100 1,000 10,000 100,000 1,000,000
As the number is being typed.
Initially I thought it would be a neat feature to have, but I'm concerned it may be confusing. Would it be better to format the number when focus on the input box is lost?
A similar question. These input boxes also have a maximum value that can be entered. If the user types a value outside the valid range, should the input instantly auto correct to the max value, or only do so when input focus is lost? If waiting till focus is lost, should you 'silently' change to the max value, or highlight the box with some kind of error display?