<button id="dropdownbutton" type="button">Button</button>
<script>
    $("#dropdownbutton").kendoDropDownButton({
        items:[
            { id: "item1", text: "item 1" },
            { id: "item2", text: "item 2" }
        ],
        open: function(e) {
            console.log("Opened!");
        }
    });
</script>