问查找委派的evt div的子项- jQuery

EN

<div id="main-randompart"> <!--This is added to the DOM as the web runs-->
    <div class="close">
        X
    </div>
    <img src="somesrc...">
</div>

<script>
    $(document).ready(function () {
         let r = 'randomtext...'; //Here I have the randompart
         let s = '#main-' + r;             
         $("div").on("click", s, function (){
             let main = $(this);
             console.log(main); //returns the element
             console.log(main.find("img")); //returns nothing
             console.log(main.children()[1]); //returns something like: <img src="some_src..." 
         });
    });
</script>