I noticed that figure 4-2, example code for attr() using the planets (pg. 98), doesn't work in IE 7 and was wondering if anyone had commented on this or why IE is unable to have it's ID attribute set. Fortunately the href can be set so it appears to be limited to only certain attributes.
It works fine in Firefox, but I think in future publishings I would add this into any editorial changes so developers who may not go through every exercise realize there are limitations with this particular sample.
Would like to see a work-around for this.