How to get full classname with xpathquery? - xpath

Question

I'm parsing through a HTML document and I need a class name of a div. I know a part of the class name (that never changes) but I need the full class name.
Here's the code I use:
$doc = new DOMDocument;
$doc->loadHTMLFile('http://some_website.com');
$xpath = new DOMXPath($doc);
$classname_of_the_div=$xpath->query('//div[#class="part_of_the_class_name_that_never_changes"]');
When I var_dump() the $classname_of_the_div and $classname_of_the_div->item(0) the result is:
object(DOMNodeList)#3 (1) { ["length"]=> int(0) }
NULL
I know that $classname_of_the_div=$xpath->evaluate('string(//div[#class="part_of_the_class_name_that_never_changes"])'); gives me the content of the div but how do I get the full class name?
P.S.: The part of the classname is separated from the rest of the class name by white spaces, so it's not really a part of the class. The div has just several classes.

Answer 1

I mean the div has several class names like - I want to select it by "class2" for example and receive the
full class string including "class1 class2 class3"
Then, an XPath expression like
//div[#class="part_of_the_class_name_that_never_changes"]
will never yield a result, save for the situation that a particular div element only has one class, that is, the one "that never changes". That's because the XPath expression above means:
Select div elements that have a class attribute whose string value
exactly corresponds to "part_of_the_class_name_that_never_changes".
But imagine the following situation:
<div class="part_of_the_class_name_that_never_changes other_class1 other_class2"/>
Then, you would need to change the expression to:
//div[contains(#class,'part_of_the_class_name_that_never_changes')]/#class
The expression means:
Look for div elements that have a class attribute whose string
value contains the string
"part_of_the_class_name_that_never_changes" and return the attribute
value.