How to check if TAG exists inside XML with PHP?

Question

How to check if a TAG name exists inside an XML file.

so if i want to get

$dom->getElementsByTagName('error')

and it does not exist, it outputs something like an error message.

EDIT:

I work from an API. So what happens when a user enters an invalid username, other XML files containing the <error> tag are loaded.

However, if they enter the correct username, the XML file does not contain an <error> , so I'm looking for a way to check if an error tag exists inside XML.

Answer 1

 $dom = new DOMDocument(); $dom->load( 'some.xml' ); $errorNodes = $dom->getElementsByTagName('error'); if($errorNodes->length == 0) { message('no error nodes'); // user defined } 

Answer 2

 $errors = $dom->getElementsByTagName('error'); $exists = $errors->length > 0; if (!$exists ) { echo 'Error message..'; } 

Answer 3

 $error=false; $AllElements = $xmlDoc->getElementsByTagName('*'); foreach ($AllElements as $OneElement) { if (($OneElement->tagName)=='error') { $error = true; } } if $error { message('error'); // user defined } else { message('no error nodes'); // user defined }