main.js

/*--------------------------------------------
	Scroll up 
	---------------------------------------------*/
	jQuery(function($){
		jQuery.scrollUp({
			 scrollText: '<i class="fa fa-angle-up"></i>'
		});
	});

Scroll to Up

1. call scrollup.js on your file
2. call css code on style.css
3. active scroll up 

scrollup.js

/*

 scrollup v2.0.0
 Author: Mark Goodyear - http://markgoodyear.com
 Git: https://github.com/markgoodyear/scrollup

 Copyright 2013 Mark Goodyear.
 Licensed under the MIT license
 http://www.opensource.org/licenses/mit-license.php

 Twitter: @markgdyr

 */
!function(a,b,c){a.fn.scrollUp=function(b){a.data(c.body,"scrollUp")||(a.data(c.body,"scrollUp",!0),a.fn.scrollUp.init(b))},a.fn.scrollUp.init=function(d){var e=a.fn.scrollUp.settings=a.extend({},a.fn.scrollUp.defaults,d),f=a("<a/>",{id:e.scrollName,href:"#top",title:e.scrollText}).appendTo("body");e.scrollImg||f.html(e.scrollText),f.css({display:"none",position:"fixed",zIndex:e.zIndex}),e.activeOverlay&&a("<div/>",{id:e.scrollName+"-active"}).css({position:"absolute",top:e.scrollDistance+"px",width:"100%",borderTop:"1px dotted"+e.activeOverlay,zIndex:e.zIndex}).appendTo("body"),scrollEvent=a(b).scroll(function(){switch(scrollDis="top"===e.scrollFrom?e.scrollDistance:a(c).height()-a(b).height()-e.scrollDistance,e.animation){case"fade":a(a(b).scrollTop()>scrollDis?f.fadeIn(e.animationInSpeed):f.fadeOut(e.animationOutSpeed));break;case"slide":a(a(b).scrollTop()>scrollDis?f.slideDown(e.animationInSpeed):f.slideUp(e.animationOutSpeed));break;default:a(a(b).scrollTop()>scrollDis?f.show(0):f.hide(0))}}),f.click(function(b){b.preventDefault(),a("html, body").animate({scrollTop:0},e.topSpeed,e.easingType)})},a.fn.scrollUp.defaults={scrollName:"scrollUp",scrollDistance:300,scrollFrom:"top",scrollSpeed:300,easingType:"linear",animation:"fade",animationInSpeed:200,animationOutSpeed:200,scrollText:"Scroll to top",scrollImg:!1,activeOverlay:!1,zIndex:2147483647},a.fn.scrollUp.destroy=function(d){a.removeData(c.body,"scrollUp"),a("#"+a.fn.scrollUp.settings.scrollName).remove(),a("#"+a.fn.scrollUp.settings.scrollName+"-active").remove(),a.fn.jquery.split(".")[1]>=7?a(b).off("scroll",d):a(b).unbind("scroll",d)},a.scrollUp=a.fn.scrollUp}(jQuery,window,document);

style.css

	/* Scroll to up css*/
	a#scrollUp {
	  background: orange none repeat scroll 0 0;
	  bottom: 20px;
	  color: #fff;
	  font-size: 20px;
	  height: 35px;
	  padding: 4px;
	  right: 20px;
	  text-align: center;
	  width: 30px;
	}