IE7 element.getAttributeNode('value').specified == null

On IE

when element is dom node &lt;option&gt;
element.getAttributeNode('value').specified == null ko crashes
tested on ie8, ie9, ie10 in compatibility view

in knockout 2.2.1.debug.js

from line 1455

                                return ko.utils.ieVersion <= 7
                                    ? (element.getAttributeNode('value').specified ? element.value : element.text)
                                    : element.value;

should be 

                                return ko.utils.ieVersion <= 7
                                    ? (element.getAttributeNode('value')!=null && element.getAttributeNode('value').specified ? element.value : element.text)
                                    : element.value;