@@ -5,7 +5,7 @@ if (ariaHeadingLevel !== null) {
 	return true;
 }
 
-var headingLevel = node.tagName.match(/H(\d)/);
+var headingLevel = node.nodeName.match(/H(\d)/);
 
 if (headingLevel) {
 	this.data(parseInt(headingLevel[1], 10));
var ariaHeadingLevel = node.getAttribute('aria-level');

if (ariaHeadingLevel !== null) {
	this.data(parseInt(ariaHeadingLevel, 10));
	return true;
}

var headingLevel = node.tagName.match(/H(\d)/);

if (headingLevel) {
	this.data(parseInt(headingLevel[1], 10));
	return true;
}

return true;

do you need `toUpperCase()` here?