Display a custom field values Dropdown ​​based on value of another dropdown field by java script

unknown

I want to display a custom field values Dropdown ​​based on value of another dropdown field by java script only, please let me know 

I have 3 field the all are drop down

CF1,CF2, CF3 

In which the value of CF2 depend on value selected n CF1

and value of CF3 depend on value selected n CF2

Nic Brough -Adaptavist-

You could try to inject some quite complex javascript, but that's a flaky solution at best, and unlikely to work in full, as there are several places you'd need to implement variants of it.

You would be better off doing it with an add-on.

The spec you've got there is pretty much what the "multi-level cascading select" add-on is for.

If you don't want to do that, or have other different dependent-field type things to do, then look to ScriptRunner "behaviours" or pick up something like "dynamic forms"