diff --git a/js/xpconnect/shell/xpcshell.cpp b/js/xpconnect/shell/xpcshell.cpp
index 5a3b51a3021..6f51ab65707 100644
--- a/js/xpconnect/shell/xpcshell.cpp
+++ b/js/xpconnect/shell/xpcshell.cpp
@@ -791,6 +791,24 @@ Parent(JSContext *cx, unsigned argc, jsval *vp)
     return true;
 }
 
+static JSBool
+Atob(JSContext *cx, unsigned argc, jsval *vp)
+{
+    if (!argc)
+        return true;
+
+    return xpc::Base64Decode(cx, JS_ARGV(cx, vp)[0], &JS_RVAL(cx, vp));
+}
+
+static JSBool
+Btoa(JSContext *cx, unsigned argc, jsval *vp)
+{
+  if (!argc)
+      return true;
+
+  return xpc::Base64Encode(cx, JS_ARGV(cx, vp)[0], &JS_RVAL(cx, vp));
+}
+
 static JSFunctionSpec glob_functions[] = {
     JS_FS("print",           Print,          0,0),
     JS_FS("readline",        ReadLine,       1,0),
@@ -805,12 +823,14 @@ static JSFunctionSpec glob_functions[] = {
     JS_FS("gczeal",          GCZeal,         1,0),
 #endif
     JS_FS("options",         Options,        0,0),
-    JS_FN("parent",     Parent,         1,0),
+    JS_FN("parent",          Parent,         1,0),
 #ifdef DEBUG
     JS_FS("dumpHeap",        DumpHeap,       5,0),
 #endif
     JS_FS("sendCommand",     SendCommand,    1,0),
     JS_FS("getChildGlobalObject", GetChildGlobalObject, 0,0),
+    JS_FS("atob",            Atob,           1,0),
+    JS_FS("btoa",            Btoa,           1,0),
     JS_FS_END
 };
 
diff --git a/js/xpconnect/src/nsXPConnect.cpp b/js/xpconnect/src/nsXPConnect.cpp
index 8303602f86a..912dca77f87 100644
--- a/js/xpconnect/src/nsXPConnect.cpp
+++ b/js/xpconnect/src/nsXPConnect.cpp
@@ -2322,7 +2322,7 @@ DeferredRelease(nsISupports *obj)
     return nsXPConnect::GetRuntimeInstance()->DeferredRelease(obj);
 }
 
-bool
+NS_EXPORT_(bool)
 Base64Encode(JSContext *cx, JS::Value val, JS::Value *out)
 {
     MOZ_ASSERT(cx);
@@ -2348,7 +2348,7 @@ Base64Encode(JSContext *cx, JS::Value val, JS::Value *out)
     return true;
 }
 
-bool
+NS_EXPORT_(bool)
 Base64Decode(JSContext *cx, JS::Value val, JS::Value *out)
 {
     MOZ_ASSERT(cx);
diff --git a/js/xpconnect/src/xpcpublic.h b/js/xpconnect/src/xpcpublic.h
index 0ae0cbab7c4..3cf242117e7 100644
--- a/js/xpconnect/src/xpcpublic.h
+++ b/js/xpconnect/src/xpcpublic.h
@@ -214,8 +214,8 @@ namespace xpc {
 bool DeferredRelease(nsISupports *obj);
 
 // If these functions return false, then an exception will be set on cx.
-bool Base64Encode(JSContext *cx, JS::Value val, JS::Value *out);
-bool Base64Decode(JSContext *cx, JS::Value val, JS::Value *out);
+NS_EXPORT_(bool) Base64Encode(JSContext *cx, JS::Value val, JS::Value *out);
+NS_EXPORT_(bool) Base64Decode(JSContext *cx, JS::Value val, JS::Value *out);
 
 /**
  * Convert an nsString to jsval, returning true on success.