DOM: get <td> element

[dummyagain]

i get something like this

<td class=abc>test</td>
<td><input class=cde name=box></td>

i would like to know how to use dom to change the class name "abc" or any other way to do it? (except assign an id to it)

Thank you

[andreasblixt]

// Instead of using the document object below, you can also get the table and use the getElementsByTagName method on that to limit the scope to that one table.
var tds = document.getElementsByTagName("TD");
for (var i = 0; i < tds.length; i++) {
var td = tds[i];
if (td.className == "abc") td.className = "def";
}