title: Jenkins: How to show/hide string parameter fields, after checkbox is un/checked?
body: <p>I need to create Jenkins job, which installs product.iso on defined machine.
  I have 2 options:
  latest.iso (path to it is already known)
  custom.iso (path have to be determined manually)</p>
  
  <p>Best implementation would be for me a checkbox named: "install custom iso"</p>
  
  <p>When user choose(check) this checkbox
  - two string parameter fields would appear below (for determine IP and PATH of custom iso.)
  When user unchecks this checkbox
  - these two string parameter fields disappear (and default latest.iso would be installed)</p>
  
  <p>I've searched through many Jenkins plugins, but it seems, that none of them allows this kind of action, which is strange to me, because I think, that this type of action is frequently needed.</p>
  
  <p>Is there any simple way to do it?
  Any help would be appreciated.</p>