如何更改jqgrid自定义格式化程序中单元格的背景颜色？

function customFormatter(cellValue, options, rowObject) {
    var cellHtml = "<div style='background-color: #FF0000;'>" + cellValue + "</div>";
    return cellHtml;
}

$("#grid").jqGrid({
    // ...
    colModel: [
        // ...
        {
            name: "exampleColumn",
            index: "exampleColumn",
            width: 100,
            formatter: customFormatter
        },
        // ...
    ]
});