checked

A Boolean value, determining whether the SplitButton is checked. This is only applicable with the toggle setting enabled.

<button id="but1"></button>

<script type="text/javascript">
     $(function () {
        $("#but1").shieldSplitButton({
            toggle: true,
            checked: true,
            dataSource: {
                data: [
                    { content: "Menu Item" }
                ]
            }
        });
     });
</script>