DropDown

HTML

<link rel="stylesheet" href="http://www.ok-soft-gmbh.com/jqGrid/jquery.jqGrid-4.1.2/css/ui.jqgrid.css">
<script src="http://www.trirand.com/blog/jqgrid/js/i18n/grid.locale-en.js"></script>
<script src="http://www.trirand.com/blog/jqgrid/js/jquery.jqGrid.min.js"></script>
<script src="http://ivaynberg.github.com/select2/select2-3.3.1/select2.js"></script>
<link rel="stylesheet" href="http://ivaynberg.github.com/select2/select2-3.3.1/select2.css">
<table id="grid"></table>

JavaScript

$(function () {
    var localData = [{
        id: '0',
        option: '1',
        Name: "One"
    }, {
        id: '1',
        option: '2',
        Name: "Two"
    }, ];
    var grid = jQuery("#grid");
    grid.jqGrid({
        datatype: 'local',
        data: localData,
        editurl: 'clientArray',
        colNames: ["Id", "option", "name"],
        colModel: [{
            name: 'id',
            index: 'id',
            width: 20
        }, {
            name: 'option',
            index: 'option',
            editable: true,
            formatter: 'select',
            edittype: 'select',
            width: 300,
            editoptions: {
                value: {
                    '1': 'This is a long text 123123123123123',
                        '2': 'The quick brown fox jumps over the lazy dog',
                        '3': '1',
                        '4': '<span>24242</span>',
                        '5': '43242',
                        '6': '{"a":"a","b","b"}',
                        '7': '<em>test</em>',
                }
            }
        }, {
            name: 'Name',
            index: 'Name'
        }, ],
        gridview: true,
        height: 'auto',
        onSelectRow: function (id) {
            jQuery('#grid').editRow(id, true);
            $("#" + id + "_option").select2({
                "width": "300"
            });
        },
        loadComplete: function () {
            var grid = $("#grid");
            var ids = grid.getDataIDs();
            for (var i = 0; i < ids.length; i++) {
                grid.setRowData(ids[i], false, {
                    height: 40
                });
            }
            grid.setGridHeight('auto');
        }

    });
});