mshtml: Implement HTMLElementCollection's toString.

dlls/mshtml/htmlelemcol.c

@@ -301,8 +301,10 @@ static HRESULT WINAPI HTMLElementCollection_toString(IHTMLElementCollection *ifa
                                                      BSTR *String)
 {
     HTMLElementCollection *This = impl_from_IHTMLElementCollection(iface);
-    FIXME("(%p)->(%p)\n", This, String);
-    return E_NOTIMPL;
+
+    TRACE("(%p)->(%p)\n", This, String);
+
+    return dispex_to_string(&This->dispex, String);
 }
 
 static HRESULT WINAPI HTMLElementCollection_put_length(IHTMLElementCollection *iface,

dlls/mshtml/tests/documentmode.js

@@ -210,6 +210,7 @@ sync_test("builtin_toString", function() {
     if(clientRects) test("clientRect", clientRects[0], "ClientRect");
     if(clientRects) test("clientRects", clientRects, "ClientRectList");
     if(currentStyle) test("currentStyle", currentStyle, "MSCurrentStyleCSSProperties");
+    test("elements", document.getElementsByTagName("body"), "HTMLCollection");
     test("history", window.history, "History");
     test("implementation", document.implementation, "DOMImplementation");
     if(localStorage) test("localStorage", localStorage, "Storage");