Collapsible widgets [closed]

If you go into functions.php, then there are most likely a place where it says:

register_sidebar( array(
  'name'          => __( 'Footer, column one', 'lang_token' ),
  'id'            => 'footer_col_one',
  'before_widget' => '<div id="%1$s" class="single-widget %2$s">',
  'after_widget'  => '</div>',
  'before_title'  => '<h4 class="widget-title">',
  'after_title'   => '</h4>',
) );

That is where the widget is registered. Then you can add a class to the given widget, like this:

register_sidebar( array(
  'name'          => __( 'Footer, column one', 'lang_token' ),
  'id'            => 'footer_col_one',
  'before_widget' => '<div id="%1$s" class="single-widget %2$s MyNewSuperDuperClass">',
  'after_widget'  => '</div>',
  'before_title'  => '<h4 class="widget-title">',
  'after_title'   => '</h4>',
) );

And then you could find that class and fold the widget with some javascript. Remember, that you need something client-side, in order to make the visitor fold/unfold it. I would probablyly do it with CSS and a button, – but you could also do it with jQuery, something along these lines.