How to clear all s’ contents inside a parent ?

Answer 1

You can use .empty() function to clear all the child elements

 $(document).ready(function () {
  $("#button").click(function () {
   //only the content inside of the element will be deleted
   $("#masterdiv").empty();
  });
 });

To see the comparison between jquery .empty(), .hide(), .remove() and .detach() follow here http://www.voidtricks.com/jquery-empty-hide-remove-detach/