Fix IE9< Array.indexOf() error

Author: Dev-Speranza

source/js/jquery-sortable.js

@@ -146,6 +146,32 @@
     array.length = from < 0 ? array.length + from : from;
     return array.push.apply(array, rest);
   }
+	function indexOf(array, elem) {
+        var t = Object(array);
+        var len = t.length >>> 0;
+        if (len === 0) {
+            return -1;
+        }
+        var n = 0;
+        if (arguments.length > 1) {
+            n = Number(arguments[1]);
+            if (n != n) { // shortcut for verifying if it's NaN
+                n = 0;
+            } else if (n != 0 && n != Infinity && n != -Infinity) {
+                n = (n > 0 || -1) * Math.floor(Math.abs(n));
+            }
+        }
+        if (n >= len) {
+            return -1;
+        }
+        var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);
+        for (; k < len; k++) {
+            if (k in t && t[k] === elem) {
+                return k;
+            }
+        }
+        return -1;
+	}
 
   function setDimensions(array, dimensions, useOffset) {
     var i = array.length,
@@ -387,7 +413,8 @@
       this.containers.push(container);
     },
     removeContainer: function (container) {
-      var i = this.containers.indexOf(container)
+      //var i = this.containers.indexOf(container)
+      var i = indexOf(container,this);
       remove(this.containers, i);
     },
     scrolled: function  (e) {