You can help users contribute useful information by testing their text entries
against rules you configure.
Text fields can be error-prone because they invite free-form input. You can help
users provide usable information by automatically rejecting values that don't match the
needs of the tracker.
This simplifies things for the user, but for the tracker
administrator it can be complicated. So let's look at an example.
Note: If your
goal is to require users to enter some value, whatever the value is, don't
use text field validation. Select the Required option
instead.
Notice that any field in which you are validating text entries is identified by
Text Entry (with Field Validation) when listed on the TRACKER
FIELDS
tab.