Just a snippet to make a bar fixed with a given breakpoint and lower element to adjust

sticky.js

$.fn.sticky = function( options ){
 
  console.error( options );

  var element    = $( this );
  var breakpoint = options.breakpoint;
  var container  = $( options.container );
 
 
 
  var detect_breakpoint = function() {
    var scroll = $( document ).scrollTop();
  
    // get the height
    var padding   = element.outerHeight();
 
    // check to see if scroll has exceeded the navigation height
    var has_exceeded = ( scroll > breakpoint );
 
    if( has_exceeded ) {
 
      // set the element position as fixed
      element.css( 'position', 'fixed' );
 
      // set the position on top
      element.css( 'top', 0 );
 
      // add a `padding-top` to the container with the element's height
      container.css( 'padding-top', padding );
      
    } else {
 
      // set the element position to static
      element.css( 'position', 'static' );      
 
      // remove the container `padding-top`
      container.css( 'padding-top', 0 );
 
    }
  }
 
  $( window ).scroll( detect_breakpoint );
 
  return $( this );
 
};