Get value of the object by attribute value

I'm stuck a little at this point. Let's say, we have this XML:

<object>
    <data name="my name">Alex</data>
    <data name="somebody's name">Dan</data>
</object>

In PHP, I can select value of the object by simplexml's XPath:

<?
$result = $xml->xpath('/object/data[@name="my name"]'); //array of values
echo $result[0]; //output: Alex
?>

But I can't get it: how can I do the same using javascript? I mean, is there any method like .getElementByTagName(), but for attribute's value?

Thank you.