Need some help with DOM

[AHA7]

Hello,

 

Say, that I have an HTML page with many tables and with each table has a unique class (styling) for its rows that is different from other tables'. I use the dom class (DomDocument()) to load the HTML page for other purposes but it would be nice if I could achieve this using dom functions as follows:

 

I want to get the attribute class (its value) of the first, and only the first, childnode (<tr>) of each table on the page. Note: each <tr> element in all tables has its own class attribute with unique value to each table. All the rows (<tr>'s) of the same table has the same value for their class attribute.

 

How can I do that?