The attributes for a given node can be retrieved using the attributes() method, which returns an array of attributes for that node. 

<?php
    tidy_parse_file('test.html');
    $body = tidy_get_body();
    foreach($body->attributes() as $attr) {
    
        if($attr->id == TIDY_ATTR_BGCOLOR) {
            echo "The background color is: '{$attr->value}'";
        }
        
    }
    
?>
The get_attr() method is a shorthand version of above and allows you to retrieve a specific attribute object with less code: 

<?php
    tidy_parse_file('test.html');
    $body = tidy_get_body();
    $attr = $body->get_attr(TIDY_ATTR_BGCOLOR);
    echo "The background color is: '{$attr->value}'";
?>