FF下设置表格单元格宽度不好用，郁闷！

部分代码如下：
 if(document.uniqueID)//IE浏览器
                {
                    cell1.style.cssText = "width:10px;";
                    cell1.setAttribute("align","center");
                    cell2.style.cssText = "width:260px;";
                }
                else//其他浏览器
                {
                   cell1.setAttribute("style","width:10px;");
                   cell1.setAttribute("align","center");
                   cell2.setAttribute("style","width:260px;");
                }
                row.appendChild(cell1);
                row.appendChild(cell2);
                             document.getElementById(controlId).appendChild(row);在IE下没有问题，在FF下就宽度就变了，到底什么原因？