Scroll to top with a small div toggling fixed in bottom-right corner only when needed

scrollToTop.js

/*
Scroll to top
*/


function scroll_to_top(ID){         
	if (document.getElementById(ID)){
		$('#'+ ID).append('<a href="#top" id="scrollToTop">haut de page</a>');

		$(window).scroll(function() {
			if($(window).scrollTop() == 0){
				$('#scrollToTop').fadeOut("fast");
			} else {
				$('#scrollToTop').fadeIn("fast");
			}
		});
		 
		$('a[href=#top]').click(function(e){
			$('html, body').animate({scrollTop:0}, 'slow');
			event.preventDefault();
		});
	}
}//end of scrolltop()	 
scroll_to_top('main');

scrollToTop.scss

/*
Scroll to top CSS
*/

#scrollToTop {
@include transition(all 0.5s ease-in-out);
position: relative;
display: block;
margin-top: 1em;
margin-left: 1em;
float: right;
text-align:center;
opacity: 0.6;
color: $gray;

  &:before {
		display: block;
		float: left;
		font-family: $iconFontFamily;
		content: $top;
		color: $red;
		font-size: 3em;
		margin-top: -0.2em;
		margin-right: -0.2em;
	}

	&:hover{
		opacity: 1;
	}
}