Merge pull request #110 from freestylebit/master

Added vertical padding option, made it compatible with npm

README.md

@@ -63,6 +63,26 @@ window.onload = function() {
 </script>
 ```
 
+If you want to scroll to a point on the page with some extra padding on the top, simply add the "verticalPadding" option:
+
+```html
+<div class="elevator-button">Take the elevator to the target</div>
+
+<script>
+// Elevator script included on the page, already.
+
+window.onload = function() {
+  var elevator = new Elevator({
+    element: document.querySelector('.elevator-button'),
+    targetElement: document.querySelector('#elevator-target'),
+    verticalPadding: 100,  // in pixels
+    mainAudio: '/src/to/audio.mp3',
+    endAudio: '/src/to/end-audio.mp3'
+  });
+}
+</script>
+```
+
 If you're really serious (boring), you don't have to use audio... and can also set a fixed time to scroll to the top
 ```html
 <div class="elevator-button">Back to Top</div>

elevator.js

@@ -24,6 +24,7 @@ var Elevator = function(options) {
     var startPosition = null;
     var endPosition = 0;
     var targetElement = null;
+    var verticalPadding = null;
     var elevating = false;
 
     var startCallback;
@@ -61,6 +62,11 @@ var Elevator = function(options) {
             verticalOffset += element.offsetTop || 0;
             element = element.offsetParent;
         }
+
+        if ( verticalPadding ) {
+          verticalOffset = verticalOffset - verticalPadding;
+        }
+
         return verticalOffset;
     }
 
@@ -138,7 +144,7 @@ var Elevator = function(options) {
 
     function updateEndPosition() {
         if(targetElement){
-            endPosition = getVerticalOffset(targetElement);            
+            endPosition = getVerticalOffset(targetElement);
         }
     }
 
@@ -174,7 +180,7 @@ var Elevator = function(options) {
                 mainAudio.currentTime = 0;
             }
 
-            updateEndPosition();            
+            updateEndPosition();
             window.scrollTo(0, endPosition);
         }
     }
@@ -227,6 +233,10 @@ var Elevator = function(options) {
             targetElement = _options.targetElement;
         }
 
+        if( _options.verticalPadding ) {
+            verticalPadding = _options.verticalPadding;
+        }
+
         window.addEventListener('blur', onWindowBlur, false);
 
         if( _options.mainAudio ) {
@@ -250,4 +260,6 @@ var Elevator = function(options) {
     }
 
     init(options);
-};
+};
+
+module.exports = Elevator;

package.json

@@ -0,0 +1,19 @@
+{
+  "name": "elevator.js",
+  "version": "1.0.0",
+  "description": "Elevator.js fixes those awkward \"scroll to top\" moments the old fashioned way.",
+  "main": "elevator.min.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/tholman/elevator.js.git"
+  },
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/tholman/elevator.js/issues"
+  },
+  "homepage": "https://github.com/tholman/elevator.js#readme"
+}