Wordpress ajax没有在functions.php中调用函数

I wrote an ajax call in the front end. I wrote the server side in functions.php

function updateCont(){
    global $wpdb;
    $post_id = $_POST['post_id'];
    $key = $_POST['key'];
    $value = $_POST['value'];

    update_post_meta($post_id, $key, $value);
    echo $value;
    die();
}
add_action('wp_ajax_updateCont', 'updateCont');
add_action('wp_ajax_nopriv_updateCont', 'updateCont'); 

My jquery is as follows

jQuery.ajax({
            type:"POST",
            url: "<?php echo admin_url('admin-ajax.php'); ?>",
            data: {"post_id":<?php echo get_the_ID();?>, "key":"top_left_content", "value":"new content"},
            success:function(data){
                console.log(data);// is 0
            }
        });

However, the data returned from the ajax call is always "0" When I searched for it, people say my function is not loaded into wordpress. I don't understand what to do here.