is validation in jira without a workflow transition possible for custom fields?

[Ganga Bopaiah]

I have a field called "Fixed versions" and if users enter a value to it, another field called "HF Approver" should not be empty,validation needs to happen without a transition. Is data validation possible? if yes, how?

[Michael Partyka]

It is possible but it is not recommended. You can use custom html and javascript in a cusotmfield.

Read this:

https://confluence.atlassian.com/jira/fields-allowing-custom-html-or-javascript-224401453.html

[Nic Brough -Adaptavist-]

Not natively.  You could try javascript, but Atlassian are gradually removing the ability to do javascript hacks in fields, as they're generally horrid and often security risks.

The Behaviours module of the Script Runner add-on can do some of this though - there may be other add-ons that can do it, but I've only ever used Behaviours.