diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testInvalidCharCodeAt.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testInvalidCharCodeAt.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+function doTestInvalidCharCodeAt(input)
+{
+    var q = "";
+    for (var i = 0; i < 10; i++)
+       q += input.charCodeAt(i);
+    return q;
+}
+function testInvalidCharCodeAt()
+{
+    return doTestInvalidCharCodeAt("");
+}
+assertEq(testInvalidCharCodeAt(), "NaNNaNNaNNaNNaNNaNNaNNaNNaNNaN");