使用xpath从background-image样式属性中提取值

Ii have the follow structure:

<div class="xGh" style="background-image: url('name_file.jpg');"></div>

I need that output:

name_file.jpg

I try use that answer, but dont work fo me :

$img = $xpath->query(substring-before(substring-after(//div[@class='xGh']/@style, "background-image: url('"), "')"));    

echo $img->item($i)->nodeValue."<br/>";

Look the error:

Test Ideone with error

I have some error in that sintaxe i cant see how is correct...

sry my english

1) You lost quotes wrapping xpath - it's string.

2) with dom xpath, query returns set of nodes while to receive string result it's better to use evaluate

$img = $xpath->evaluate('substring-before(substring-after(//div[@class=\'xGh\']/@style, "background-image: url(\'"), "\')")');    

echo $img; // it contains name_file.jpg

demo