jQuery Grid Plugin - jqGrid

Is it possible to do the same using JQGrid Custom Button???  If not is there any alternate option to call custom dialog with input features other than the columns available in jqgrid!

jQuery("#List").jqGrid('navButtonAdd', '#pagerb', {
                caption: "Create",
                title: "Create List",
                onClickButton: function() {
                    //alert("hi");
                    $("#dialog").dialog({
                        bgiframe: true,
                        height: 140,
                        modal: true
                                        });

                                                       }

                                                                           });

<div id="dialog" title="Modal dialog">
                <input type="text" id="txt" />
                <input type="button" id="btn" value="Create"/>

</div>