how to open jqgrid add form when click on the custom button of jqgrid?
$("#jqgUsers").navGrid('#jqgpUsers', { edit: false, add: false, del: false, search: false })
        .navButtonAdd('#jqgpUsers', {
            caption: "",
        buttonicon: "ui-icon-plus",
        onClickButton: function () {
            alert("Adding Row");
        },
        position: "last"
    });

$(this).jqGrid("editGridRow", "new");

$(this).jqGrid("editGridRow", "new", {recreateForm: true, closeAfterAdd: true});