Better!

I was actually thinking of something along the lines of

```
var allowedAttrValue = allowedAttrs[attrName];
var notInAttrList = ! allowedAttrValue;
var valueNotAllowed = node.getAttribute(node.attributes[a].name) !== allowedAttrValue;
if (notInAttrList || valueNotAllowed) {
```

although the `notInAttrList` becomes a bit more self-explanatory in this example. I think some of the reading complexity comes from JS missing basic collection methods like "contains" or "hasKey").

Anyway, will let you do whatever you prefer here.