jQuery - scroll event with scrollTop()

Question

if($(document).width() <= 783 ){
	var main_header_top = $('.header-layout-style-1').offset().top + 0;
	if($(this).scrollTop() > main_header_top) {
		$('.slider-position').addClass('stick-top top-zero').show();				
	} else {
		$('.slider-position').removeClass('stick-top top-zero');
	}
}