( function( $ ) {
  
  /** jQuery helper functions.
   */

    $.fn.extend( {

      toggleText : function( a, b ) {

        return this.text( this.text() === b ? a : b );
      },

      inViewport : function( curr ) {

        return this.each( function( idx, elem ) {

          function visPx() {

            var elH = $( elem ).outerHeight(),
                wH  = $( window ).height(),
                rct = elem.getBoundingClientRect(), 
                top = rct.top, 
                bot = rct.bottom;

            return curr.call( elem, 
              Math.max( 0, top > 0 
                ? Math.min( elH, wH - top ) 
                : Math.min( bot, wH ) ) 
              );  
          }
       
          visPx();
       
          $( window ).on( 'resize scroll', visPx );
        } );
      }
    } );

} ) ( jQuery );