bind setAttribute() on form value change

Question

basic jquery question: I have a select2 select where i want to change a CSS background image of a div based on which option is selected and pass it django view context.

on change, I can temporarily set the background img, but it only lasts during the change event, then reverts back and gets overwritten by the style file. the other issue is that {{ cover_image_url }} which is django template context displays the last select {{ cover_image_url }} value, not the current one (ex: change select from N1 to N2, no background-image change. change select form N2 to N3, it displays background-image for N2 not N3)

how can I bind the change so it's permanent until the page reloads or the select option is changed again? thanks

<script>
$(document).ready(function() {
    $('.tags').select2({
        selectOnClose: true
    }).on("change", function(e){
        if(this.value != "/"){
            // set this background until the next change
            document.getElementById("image-div").setAttribute("style","background-image:url('{{ cover_image_url }}')!important;")
        }
    });
});
</script>