title: Magento admin grid massaction checkboxes default checked & option set to action I want
body: <p>Just like the question <a href="https://magento.stackexchange.com/questions/19179/keep-the-checkboxes-of-mass-action-checked-for-some-items-by-default">keep the checkboxes of mass action checked for some items, by default</a>, but I simply want all checkboxes checked by default, plus a default mass-action is selected on first landing.</p>
  
  <p>E.g. a landing grid page:
  <img src="https://i.stack.imgur.com/Jamal.png" alt="Screenshot"></p>
  
  <p>Should I just use JS to select them? Or there is a simpler way?</p>