Moved old functions into object

parallax.js

@@ -1,20 +1,39 @@
 var Parallax = {
-    initialise: function() {
+    initialise: function(createEvents) {
-
+        $(this.ident).each(function(){
+            // Calculate Offset
+            inset = $(this).attr('parallax-inset');
+            image_height = $(this).height();
+            range = image_height / inset;
+            $(this).attr('parallax-offset', range / 2);
+        });
+        console.log("Parallax Initialised.");
+        if (createEvents) {this.createEvents();}
+        this.calculate();
     },
     calculate: function() {
+        window_top = $(window).scrollTop();
+        window_bottom = window_top + $(window).height();
+        $(this.ident).each(function(){
+            if (!is_on_screen(this) || !$(this).attr('parallax-offset') != false) { return; }
+            element = $(this);
+            center_pos = (element.offset().top - $(window).scrollTop()) + (element.height() / 2);
+            perc = -(0.5 - ((window_top - center_pos) / window_bottom));
 
+            pos = Math.round((perc * element.attr('parallax-offset')) * 100) / 100;
+            element.css('background-position',"0px " + pos + "px");
+        });
     },
-    events: function() {
+    createEvents: function() {
-
+        $(window).scroll(function() { Parallax.calculate(); });
+        $(window).resize(function() { Parallax.initialise(); })
     },
     ident: '.parallax'
 }
 
 function is_on_screen(elm) {
-
+    var vpH = $(window).height(),
-    var vpH = $(window).height(), // Viewport Height
+        st = $(window).scrollTop(),
-        st = $(window).scrollTop(), // Scroll Top
         y = $(elm).offset().top,
         elementHeight = $(elm).height();
     return ((y < (vpH + st)) && (y > (st - elementHeight)));