html - Detect CSS class in a page and write if/else in PHP -

i have page need detect css class , apply if/else statement using php. how do that?

html

<body>     <div class="insights">         hello world     </div> </body>

what php code detect , find "insights" class exists , show "yes, exists". if there's no class of name show "no, doesn't exists."

how should achieve this?

a simple solution use strpos

$contains = str($html, 'class="insights"') !== false;

a more complex , robust solution be, use regular expression following

class="[^"]*\binsights\b[^"]*"

this used in php this

$contains = (bool) preg_match('/class="[^"]*\binsights\b[^"]*"/', $html);

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