Untitled

//HTML
...
<body>
    <div class="divClassSelector" numberDiv="1"></div>
    <button id="plusOneDiv">+1 Div</button>
</body>
...

//My JS:

//Code to alert the div's numberDiv attribute value
$(".divClassSelector").on("click", function(){
    var numberDiv = (this).attr("numberDiv");
    alert(numberDiv);
});

//Code to insert another div
var count = 2;
$("#plusOneDiv").click(function(){
    $(body).append(<div class="divClassSelector" numberDiv="'+count+'">');
    count++;
});