app.js

$(function(){
  $('*[data-repeat]').each(function(){
    var n = $(this).data('repeat');
    var parent = $(this).parent();
    self = $(this);
    for (var i = 0; i < n; i++) {
      parent.append(self.clone());
    }
  })
});

index.html

<section>
  <div data-repeat="10">This is my content</div>
</section>