is_front_page() variable not found

Question

I am trying to do what should be really simple, but somehow this is driving me mad. I try to have a code snippet only run on the front page. My site is set to have a static front page so I think my key to success is the conditional tag is_front_page(). However, I cannot get it to run as no matter what I try, I always end up with an error message in the console saying “ReferenceError: Can’t find variable: is_front_page”.

Here is my very basic code that I am using to only test if the conditional tag is working:

<?php
add_action('wp', function(){; ?>
<script>
    window.addEventListener("load", function() {
        if( is_front_page() ){
            console.log("front page")
        };
    }); 
</script>
<?php });

I already spend hours browsing through the internet and found that conditional tags only work after certain elements have been loaded, hence I hooked the function in ‘wp’. Also, I have read that some similar issues were resolved by restoring the original wp_query, so I added <?php wp_reset_query();?>, but again, no change. I have also tried using is_home(), but ended up with the same error message. Also, I have disabled all plugins, no change. It is really strange as I don’t even get neither is_home() nor is_front_page() to run, so I figure there must be some rather general issue.

Any help is appreciated. Regards, happy easter and stay safe! Dominik

Answer 1

There are several issues with your code. is_front_page() is a PHP function, you need to call it within <?php ?>.

The script need to be printed in HTML in order to make it work. Try this..

function wpse_363853_run_on_front() {
    ?>
    <script>
        window.addEventListener("load", function() {
            <?php if( is_front_page() ){ ?>
            console.log("front page");
            <?php } ?>
        });
    </script>
    <?php
}
add_action( 'wp_head', 'wpse_363853_run_on_front', 99 );

Just a note, avoid using anonymous functions.