Or when making payments by "paperless" check over the phone or online.These routing numbers include a checksum digit which can be used to help verify if a given number is valid or not. You can usually find your own bank's routing number printed on your checks (look for a nine-digit number at the bottom center of the check).
If you're setting up a calendar of future events you would check that the year is the current year or greater.
When capturing information for insertion into a database, or use in other processing, it's important to control what the user can enter.
Otherwise you can end up with values in the database that have no relation to reality.
In this example, the date fields will only accept input that matches the pattern 'dd/mm/yyyy' (this could just as easily be changed to 'yyyy-mm-dd' or 'mm/dd/yyyy').
The time field will allow input starting with 'hh:mm' following by an optional 'am' or 'pm'. The code behind the form is as follows: For each field in the form (first the dates, then the time field), a check is made as to whether the input is blank.