Custom body attributes (change filter to apply to any other element) Credits: http://wpbeaches.com/adding-attribute-html-section-genesis/

custom_body_attributes.php

add_filter( 'genesis_attr_body', 'custom_add_css_attr' );
function custom_add_css_attr( $attributes ) {
 
 // add original plus extra CSS classes
 $attributes['class'] .= ' parallax';
  $attributes['data-diff'] = '100';
 // return the attributes
 return $attributes;
 
}