replace lang.arrayIndexOf with ES5 indexOf()

plugins/pilot/fixoldbrowsers.js

@@ -49,6 +49,44 @@ if (!Array.isArray) {
     };
 }
 
+// from MDC
+// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/indexOf
+if (!Array.prototype.indexOf)
+{
+	Array.prototype.indexOf = function(searchElement /*, fromIndex */)
+	{
+		if (this === void 0 || this === null)
+	    	throw new TypeError();
+		
+		var t = Object(this);
+		var len = t.length >>> 0;
+		if (len === 0)
+		    return -1;
+		
+		var n = 0;
+		if (arguments.length > 0) {
+		    n = Number(arguments[1]);
+		    if (n !== n)
+		        n = 0;
+		    else if (n !== 0 && n !== (1 / 0) && n !== -(1 / 0))
+		        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] === searchElement)
+			    return k;
+		}
+		return -1;
+	};
+}
+
 /**
  * Retrieves the list of keys on an object.
  */