Wordpress AJAX：获取Json响应的功能

I'd like to get a function as Json response in my Ajax call, after the document is ready. I'm not sure if I'm on the right way but here is what I did so far:

My Html

<!--Where i want to load my function-->
<div id="applications"></div>

My Ajax/Jquery

jQuery(document).ready(function(){
    init_applications();
});
function init_applications(){
    var app_data = new FormData();
    app_data.append('action', 'applications');
    app_data.append('uid', uid);
    app_data.append('pid', pid);
    jQuery.ajax({
        method: 'post',
        url: ajaxurl,
        dataType: 'json',
        data: app_data,
        processData: false,
        contentType: false,
        beforeSend:function(data){
            //something
        },
        success:function(data) {
            $('#applications').html(data.htmlapp);
            //console.log(data);
        },
        error: function(data){
            //console.log(data);
        }
    });
    //alert("a");
}

Of course in my functions.php

add_action('wp_ajax_applications', 'applications');
function applications(){
    $uid = $_POST['uid'];
    $pid = $_POST['pid'];
    $applications = inside_applications();
    $response = array('htmlapp'=>$applications);
    wp_send_json( $response );
}

and Finally I've created my separate function always in functions.php

function inside_applications(){
   //Some html code and instructions
}

Is this possible or I'm totally out of the way? Can you please give me some directions eventually? Many thanks.

All the previous reasoning was fine, it's just matter to return values or html in the function you want include. In my case was.

function inside_applications(){
   //Some html code and instructions
   $html = '<div class="something>everything</div>';
   $html .= '<div class="solved">solved</div>';
   //Insert some if or instructions
   return $html;
}

As discussed in comments wp_send_json() hook already print() and die() so it's not necessary to do anything more. Maybe there are other better methods to accomplish that but my objective was to Ajaxify a Wordpress theme and to have separate multiple functions refreshable and ready for my jQuery calls and actions.