diff --git a/README.md b/README.md
index 36ceabe..be5cef0 100644
--- a/README.md
+++ b/README.md
@@ -155,6 +155,16 @@ slider.start();
 |get(attribute)|Get an attribute value (attributes are mostly used internally)|
 |set(attribute, value)|Set an attribute. Can be useful for storing custom data|
 
+## Browsers
+
+Ideal Image Slider has been tested on:
+
+* Chrome
+* Firefox
+* Safari (Desktop + Mobile)
+* Opera
+* IE9
+
 ## Contribute
 
 So you want to help out? That's awesome. Here is how you can do it:
diff --git a/ideal-image-slider.css b/ideal-image-slider.css
index ecc7526..e93a634 100644
--- a/ideal-image-slider.css
+++ b/ideal-image-slider.css
@@ -29,10 +29,11 @@
 
 /* Slide effect */
 .iis-effect-slide .iis-slide {
-	-webkit-transition-property: all;
-       -moz-transition-property: all;
-    	 -o-transition-property: all;
-    		transition-property: all;
+	opacity: 0;
+	-webkit-transition-property: -webkit-transform;
+       -moz-transition-property: -moz-transform;
+    	 -o-transition-property: -o-transform;
+    		transition-property: transform;
 	-webkit-transition-timing-function: ease-out;
        -moz-transition-timing-function: ease-out;
     	 -o-transition-timing-function: ease-out;
@@ -41,6 +42,7 @@
 		-ms-transform: translateX(0%);
 			transform: translateX(0%);
 }
+.iis-effect-slide .iis-current-slide { opacity: 1; }
 .iis-effect-slide .iis-previous-slide {
 	-webkit-transform: translateX(-100%);
 		-ms-transform: translateX(-100%);
@@ -51,9 +53,8 @@
 		-ms-transform: translateX(100%);
 			transform: translateX(100%);
 }
-.iis-effect-slide .iis-previous-slide { z-index: 1; }
-.iis-effect-slide .iis-next-slide { z-index: 2; }
-.iis-effect-slide .iis-current-slide { z-index: 3; }
+.iis-direction-previous.iis-effect-slide .iis-next-slide,
+.iis-direction-next.iis-effect-slide .iis-previous-slide { opacity: 1; }
 
 /* Fade effect */
 .iis-effect-fade .iis-slide {
diff --git a/ideal-image-slider.js b/ideal-image-slider.js
index 4edfdc7..a7c1706 100644
--- a/ideal-image-slider.js
+++ b/ideal-image-slider.js
@@ -62,18 +62,24 @@ var IdealImageSlider = (function() {
 	var _loadImg = function(slide, callback) {
 		if(!slide.style.backgroundImage){
 			var img = new Image();
-			img.src = slide.dataset.src;
+			img.setAttribute('src', slide.getAttribute('data-src'));
 			img.onload = function() {
-				slide.style.backgroundImage = 'url('+ slide.dataset.src +')';
+				slide.style.backgroundImage = 'url('+ slide.getAttribute('data-src') +')';
 				if(typeof(callback) === 'function') callback(this);
 			};
 		}
 	};
 
 	var _isHighDPI = function(){
-	    return ((window.matchMedia && (window.matchMedia('only screen and (min-resolution: 124dpi), only screen and (min-resolution: 1.3dppx), only screen and (min-resolution: 48.8dpcm)').matches ||
-				window.matchMedia('only screen and (-webkit-min-device-pixel-ratio: 1.3), only screen and (-o-min-device-pixel-ratio: 2.6/2), only screen and (min--moz-device-pixel-ratio: 1.3), only screen and (min-device-pixel-ratio: 1.3)').matches)) ||
-				(window.devicePixelRatio && window.devicePixelRatio > 1.3));
+	    var mediaQuery = "(-webkit-min-device-pixel-ratio: 1.5),\
+				          (min--moz-device-pixel-ratio: 1.5),\
+				          (-o-min-device-pixel-ratio: 3/2),\
+				          (min-resolution: 1.5dppx)";
+	    if (window.devicePixelRatio > 1)
+	        return true;
+	    if (window.matchMedia && window.matchMedia(mediaQuery).matches)
+	        return true;
+	    return false;
 	}
 
 
@@ -110,7 +116,9 @@ var IdealImageSlider = (function() {
 				nextSlide: 'iis-next-slide',
 				previousNav: 'iis-previous-nav',
 				nextNav: 'iis-next-nav',
-				animating: 'iis-is-animating'
+				animating: 'iis-is-animating',
+				directionPrevious: 'iis-direction-previous',
+				directionNext: 'iis-direction-next'
 			},
 			onInit: function(){},
 			onStart: function(){},
@@ -155,17 +163,26 @@ var IdealImageSlider = (function() {
 					}
 				}
 
-				_deepExtend(slideEl.dataset, slide.dataset);
-				if(slide.dataset.src){
-					// Use data-src for on-demand loading
-					slideEl.dataset.src = slide.dataset.src;
-				} else {
-					slideEl.dataset.src = slide.src;
-				}
+				if(typeof slide.dataset !== 'undefined'){
+					_deepExtend(slideEl.dataset, slide.dataset);
+					if(slide.dataset.src){
+						// Use data-src for on-demand loading
+						slideEl.dataset.src = slide.dataset.src;
+					} else {
+						slideEl.dataset.src = slide.src;
+					}
 
-				// HiDPI support
-				if(_isHighDPI() && slide.dataset.src2x){
-					slideEl.dataset.src = slide.dataset.src2x;
+					// HiDPI support
+					if(_isHighDPI() && slide.dataset['src-2x']){
+						slideEl.dataset.src = slide.dataset['src-2x'];
+					}
+				} else {
+					// IE
+					if(slide.getAttribute('data-src')){
+						slideEl.setAttribute('data-src', slide.getAttribute('data-src'));
+					} else {
+						slideEl.setAttribute('data-src', slide.getAttribute('src'));
+					}
 				}
 
 				if(href) slideEl.setAttribute('href', href);
@@ -316,6 +333,11 @@ var IdealImageSlider = (function() {
 		_addClass(this._attributes.currentSlide, this.settings.classes.currentSlide);
 		_addClass(this._attributes.nextSlide, this.settings.classes.nextSlide);
 
+		_addClass(this._attributes.container, this.settings.classes.directionPrevious);
+		setTimeout(function(){
+			_removeClass(this._attributes.container, this.settings.classes.directionPrevious);
+		}.bind(this), this.settings.transitionDuration);
+
 		if(this.settings.transitionDuration){
 			_addClass(this._attributes.container, this.settings.classes.animating);
 			setTimeout(function(){
@@ -353,6 +375,11 @@ var IdealImageSlider = (function() {
 		_addClass(this._attributes.currentSlide, this.settings.classes.currentSlide);
 		_addClass(this._attributes.nextSlide, this.settings.classes.nextSlide);
 
+		_addClass(this._attributes.container, this.settings.classes.directionNext);
+		setTimeout(function(){
+			_removeClass(this._attributes.container, this.settings.classes.directionNext);
+		}.bind(this), this.settings.transitionDuration);
+
 		if(this.settings.transitionDuration){
 			_addClass(this._attributes.container, this.settings.classes.animating);
 			setTimeout(function(){