PHP echo displays in Chrome Dev Tool, but not webpage

PHP
<?php
function console_log($output, $with_script_tags = true) {
    $js_code = 'console.log(' . json_encode($output, JSON_HEX_TAG) . 
');';
    if ($with_script_tags) {
        $js_code = '<script>' . $js_code . '</script>';
    }
    echo $js_code;
}
Source

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