diff --git a/js/encoding/DataUtils.js b/js/encoding/DataUtils.js
index 1f998af..b51bf1e 100644
--- a/js/encoding/DataUtils.js
+++ b/js/encoding/DataUtils.js
@@ -372,3 +372,17 @@
     return string;
 }*/
 
+/**
+ * Return true if a1 and a2 are the same length with equal elements.
+ */
+DataUtils.arraysEqual = function(a1, a2){
+    if (a1.length != a2.length)
+        return false;
+    
+    for (var i = 0; i < a1.length; ++i) {
+        if (a1[i] != a2[i])
+            return false;
+    }
+
+    return true;
+}
\ No newline at end of file