dojo.byId(domnode.getAttribute('aria-activedescendant')) error in IE

[liucougar]

In EmulateIE7 mode of both IE9 and IE8, if a domnode has no 'aria-activedescendant' specified, the following will lead to error:

dojo.byId(domnode.getAttribute('aria-activedescendant'))

in IE9 EmulateIE7 mode, the error is "Invalid procedure call or argument"

in IE8 EmulateIE7 mode, the error is "Invalid argument."

the problem seems to stem from the fact that, in IE8/IE9, some sort of aria support is included, so domnode.getAttribute('aria-activedescendant') would return a empty string if no 'aria-activedescendant' is specified, however, this empty string is special: it will lead to the above error in IE8/IE9

by adding a check for empty string in dojo.byId, this can be solved

NOTE: this error does not happen in real IE7, nor in native IE8 mode, nor in EmulateIE8 mode in IE9 and native IE9 mode

proposed patch:

../svn/dojo/_base/html.js

@@ -55 +55 @@
                if(typeof id != "string"){
                        return id;
                }
-               var _d = doc || dojo.doc, te = _d.getElementById(id);
+               var _d = doc || dojo.doc, te = id && _d.getElementById(id);
                // attributes.id.value is better than just id in case the
                // user has a name=id inside a form
                if(te && (te.attributes.id.value == id || te.id == id)){

[Adam Peller]

looks good to me

[liucougar]

(In [25642]) fixes #13059: fixes IE dojo.byId error in EmulateIE7 mode

!strict