1 files changed, 55 insertions, 0 deletions
diff --git a/lib/epub.js/src/utils/scrolltype.js b/lib/epub.js/src/utils/scrolltype.js
new file mode 100644
index 0000000..7d2e47b
--- /dev/null
+++ b/lib/epub.js/src/utils/scrolltype.js
@@ -0,0 +1,55 @@
+// Detect RTL scroll type
+// Based on https://github.com/othree/jquery.rtl-scroll-type/blob/master/src/jquery.rtl-scroll.js
+export default function scrollType() {
+	var type = "reverse";
+	var definer = createDefiner();
+	document.body.appendChild(definer);
+
+	if (definer.scrollLeft > 0) {
+		type = "default";
+	} else {
+		if (typeof Element !== 'undefined' && Element.prototype.scrollIntoView) {
+			definer.children[0].children[1].scrollIntoView();
+			if (definer.scrollLeft < 0) {
+				type = "negative";
+			}
+		} else {
+			definer.scrollLeft = 1;
+			if (definer.scrollLeft === 0) {
+				type = "negative";
+			}
+		}
+	}
+
+	document.body.removeChild(definer);
+	return type;
+}
+
+export function createDefiner() {
+	var definer = document.createElement('div');
+	definer.dir="rtl";
+
+	definer.style.position = "fixed";
+	definer.style.width = "1px";
+	definer.style.height = "1px";
+	definer.style.top = "0px";
+	definer.style.left = "0px";
+	definer.style.overflow = "hidden";
+
+	var innerDiv = document.createElement('div');
+	innerDiv.style.width = "2px";
+
+	var spanA = document.createElement('span');
+	spanA.style.width = "1px";
+	spanA.style.display = "inline-block";
+
+	var spanB = document.createElement('span');
+	spanB.style.width = "1px";
+	spanB.style.display = "inline-block";
+
+	innerDiv.appendChild(spanA);
+	innerDiv.appendChild(spanB);
+	definer.appendChild(innerDiv);
+
+	return definer;
+}