Update sliders.js

This update get's rid of the jump at the start of the slide. On almost every slider know to man there is a 15px jump. This one has it to. If you log out deltaX you'll see it almost always starts with -16px. That's a noticeable jump. This change fixes it so that the slide starts from 0 and smoothly goes from there.

js/sliders.js

@@ -23,6 +23,7 @@
   var slideNumber;
   var isScrolling;
   var scrollableArea;
+  var startedMoving;
 
   var getSlider = function (target) {
     var i;
@@ -82,15 +83,20 @@
     if (e.touches.length > 1 || !slider) {
       return; // Exit if a pinch || no slider
     }
+    
+    // adjust the starting position if we just started to avoid jumpage
+    if(!startedMoving) {
+      pageX += (e.touches[0].pageX - pageX) - 1;
+    }
 
     deltaX = e.touches[0].pageX - pageX;
     deltaY = e.touches[0].pageY - pageY;
     pageX  = e.touches[0].pageX;
     pageY  = e.touches[0].pageY;
 
-    if (typeof isScrolling === 'undefined') {
+    if (typeof isScrolling === 'undefined' && startedMoving) {
       isScrolling = Math.abs(deltaY) > Math.abs(deltaX);
-    }
+    } 
 
     if (isScrolling) {
       return;
@@ -104,12 +110,18 @@
                  slideNumber === lastSlide && deltaX < 0 ? (Math.abs(pageX) / sliderWidth) + 1.25 : 1;
 
     slider.style.webkitTransform = 'translate3d(' + offsetX + 'px,0,0)';
+    
+    // started moving
+    startedMoving = true;
   };
 
   var onTouchEnd = function (e) {
     if (!slider || isScrolling) {
       return;
     }
+    
+    // were done moving
+    startedMoving = false;
 
     setSlideNumber(
       (+new Date()) - startTime < 1000 && Math.abs(deltaX) > 15 ? (deltaX < 0 ? -1 : 1) : 0