You need to write a custom script and it's location will depend upon when you want the script to execute.
Radio Buttons and Check Boxes have a string value of "Off" when none have been selected and take the value assigned to the field when checked.
ok, thanks ... but I found the solution. When I go to the properties of the radio button in the Actions tab, there is a section that says "Select Trigger" and "Select Action". With these two options select the events you wanted and hide the text fields.
You are talking about a LiveCycle form and not an Acrobat form. These are 2 different products that create a PDF form and work differently at the design level. There are LiveCycle specific forums where you will get help specific to LiveCycle.
You are talking about a LiveCycle form and not an Acrobat form.
Sounds like an Acroform to me.