How can I find page element using PHP and use in IF command

I wonder if anyone can help?

I have some PHP which works fine, however I need it to only run if there is no text field on the page.

Is there a way in PHP that I can create an IF command that sees if there is a text input or if there is a certain element class and then either stops running the code if true or carries on if false.

Here is the code I need to run only if there is no text input field.

foreach ($_option->getValues() as $value1) {
        $resulta[$value1['option_type_id']]=$value1['sku'];
        $result = array_filter($resulta);
        }

Does that make sense?

Many thanks in anticipation