[Solved] I’m trying to make fixed header change it’s background-color after I scroll the page 100px

by 


jQuery(document).scroll(function() {
var y = jQuery(this).scrollTop();
    if (y > 100) {
        jQuery('#menu').addClass('scrollActive');
    } else {
        jQuery('#menu').removeClass('scrollActive');
    }
});

and just add in your CSS

#menu.scrollActive {
  background-color: blue; // or color what you want;
}

solved I’m trying to make fixed header change it’s background-color after I scroll the page 100px