jQuery + Vars

//Index
<div id="id"></div>

// Script.JS

/*
 *   How to use that thing.
 */
jQuery(document).ready(function(){
    jQuery.ajax({
        url: php_vars.adminajax,
        data:{action:"mycred_dejatuwow_point"},
        success:function(e){
            jQuery("#id").html(e);
        }
    });
});


//functions.php
<?php
function enqueueWP(){
    /*
     * Enqueuing a script that require jQuery working, not need to link jQuery CDN as before.
     */
    wp_enqueue_script(
        'script',
        get_template_directory_uri() .'/js/script.js',
        array('jquery'), // This load hosted jQuery script
        null,
        true
    );

    /*
     * Create a Javascript Variable used by script.js
     */
    $datas = array(
        'adminajax' => admin_url( 'admin-ajax.php' ), /* Create the array */
    );
    wp_localize_script(
        'script', // HANDLE: Where the var must be used
        'php_vars', // Name of the array
        $datas // Var Passed
    );
}
add_action('wp_enqueue_scripts','enqueueWP');

/*
 * Passing this var to result in script.js
 */
function mycred_dejatuwow_point() {
    echo "USER ID: ".get_current_user_id()."<br>";
}
add_action( 'wp_ajax_mycred_dejatuwow_point', 'mycred_dejatuwow_point');    // If called from admin panel
add_action( 'wp_ajax_nopriv_mycred_dejatuwow_point', 'mycred_dejatuwow_point');