Open

<div id="toolbar"></div>
<script>
    $("#toolbar").kendoToolBar({
        items: [
            { type: "splitButton", id: "splitButton", name: "splitButton", text: "Split Button", menuButtons: [
                { id: "option1", text: "Option 1" },
                { id: "option2", text: "Option 2" },
                { id: "option3", text: "Option 3" },
                { id: "option4", text: "Option 4" }
            ] }
        ],
        open: function(e) {
/* The result can be observed in the DevTools(F12) console of the browser. */
            console.log("open", e);
        }
    });
</script>

<div id="toolbar"></div>
<script>
    $("#toolbar").kendoToolBar({
        items: [
            { type: "splitButton", id: "splitButton", name: "splitButton", text: "Split Button", menuButtons: [
                { id: "option1", text: "Option 1" },
                { id: "option2", text: "Option 2" },
                { id: "option3", text: "Option 3" },
                { id: "option4", text: "Option 4" }
            ] }
        ]
    });

    var toolbar = $("#toolbar").data("kendoToolBar");
    toolbar.bind("open", function(e){
/* The result can be observed in the DevTools(F12) console of the browser. */
        console.log("open", e);
    });
</script>