For when you want an object in a container to fill the remaining height in a container object. Such as when you have a toolbar and want the content adjacent to it to fill the remaining height of the container div.

jQuery.fillRemainingHeight()

// e.g. $("#my-child-div").fillRemainingHeight();
(function( $ ){
  $.fn.fillRemainingHeight = function( ) {
  	return this.each(function () {
	  	var $this = $(this),
	  		_h = $this.parent().height(),
	  		_used = 0;
	  	$this.siblings().each(function(){ _used+= $(this).outerHeight(); });
	  	$this.css("height", _h - _used);
  	});
  };
})( jQuery );

$("#my-child-div").css("flex":"1").parent().css({"display":"flex","flex-direction":"column"});