JavaScript

$( ".inner-switch" ).on("click", function() {
    if( $( "body" ).hasClass( "light" )) {
      $( "body" ).removeClass( "light" );
      $( ".inner-switch" ).text( "AV" );
    } else {
      $( "body" ).addClass( "light" );
      $( ".inner-switch" ).text( "PÅ" );
    }
});