javascript

CHAPTER 7 ■ TRAVERSING AND MODIFYING THE DOM TREE
But a NamedNodeMap is called a NamedNodeMap for a reason. You can, you know, query members by
name, with an identifier and the . operator or with a string and the [] operator. Try both ways, verifying
your work with Figure 7–15:
var arrayOfAttrNodes = document.getElementById("twitter").attributes;
arrayOfAttrNodes.id.value;
// "twitter"
var arrayOfAttrNodes = document.getElementById("twitter").attributes;
arrayOfAttrNodes["class"].value;
// "sprite"
Figure 7–15. Querying attributes with refinement operators
In regard to Node.attributes, Internet Explorer again says, “Ill be on my own side. By myself.” Prior
to version 8, Internet Explorer put every default attribute from the DTD in an element’s attributes
member. So, there might be like 100 in there. Yipes! Internet Explorer 8 does not have the bug.
Let’s take a moment to sigh ruefully over this Internet Explorer bug. Then find a workaround for
Internet Explorer 7 and earlier.
Hmm.
Why don’t we...
No, that won’t work.
I know, filter the Attr nodes in attributes by their specified member. Just throw away the ones
with a value of false. Click Clear in both Firebug panels, and then define a helper function named
filterDefaultAttrNodes() like so:
function filterDefaultAttrNodes(elem) {
var filtered = [];
for (var i = 0, j = elem.attributes.length; i < j; i ++) {
if (elem.attributes[i].specified) {
filtered.push(elem.attributes[i]);
}
}
return filtered;
}
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