Include a back-to-top Button on scrolling down (#446)

* Update index.html

* Create scrollToTop.js

* Update demo.css

* Update index.html

examples/demo.css

@@ -137,3 +137,24 @@ h1 {
   height: auto;
 }
 
+.move-up {
+    position: fixed;
+    bottom: 50px;
+    right: 40px;
+    z-index: 3;
+    display: none;
+    z-index:1000;
+}
+.move-up button {
+    background:transparent;
+    border:none;
+}
+.move-up button:active:hover {
+    padding-right:4px !important;
+    margin-right:2px;
+}
+.move-up i {
+    font-size:60px;
+    opacity:0.5;
+    color:#BABABA;
+}

examples/index.html

@@ -26,6 +26,9 @@
 
   <!-- Download.js for large files -->
   <script src="../node_modules/downloadjs/download.min.js" type="text/javascript"/>
+  
+  <script src="lib/scrollToTop.js"></script>
+  
 </head>
 
 
@@ -123,6 +126,9 @@
   </div>
     <button class="btn btn-primary btn-lg" name="save-sequence" id="save-seq">Save Sequence</button>
 </div>
+<form class="move-up" action="#up">
+    <button><i class="fa fa-arrow-circle-o-up"></i></button>
+</form>
   <script type="text/javascript">
     $(function() {
       var sequencer;

examples/lib/scrollToTop.js

@@ -0,0 +1,17 @@
+$(document).ready(function($){
+	$(function(){
+		$(window).scroll(function(){
+			if ($(this).scrollTop() > 100){
+				$('.move-up').fadeIn();
+			} else {
+				$('.move-up').fadeOut();
+			}
+		});
+		$('.move-up button').click(function(){
+			$('body,html').animate({
+				scrollTop: 0
+			}, 800);
+			return false;
+		});
+	});
+});