var _rating = new Array;
var _links = app.activeDocument.links;
for (var i = 0; i < _links.length; i++)
{
try
{
_rating.push(_links[i].name + ': ' + _links[i].linkXmp.getProperty("http://ns.adobe.com/xap/1.0/", "xmp:Rating"));
}
catch(e)
{
_rating.push(_links[i].name + ': ' + e);
}
}
alert( 'Rating:\n' + _rating.join('\n'));