js中给tabel动态添加行

页面：

<table id="exhibitsTr" border="0" cellspacing="0" cellpadding="0" class="edit-table">
             	 				<tr>
					                <td align="center" width='30%'>展品名称</td>
					                <td align="center" width='30%'>图片</td>
					                <td align="center" width='30%'>展品介绍</td>
					                <td align="center" width='30%'><input name="button" type="button" style="width: 96px" onclick="javascript:additem();" value="添加"/></td>
					            </tr>
             	 			</table>

js:

function additem()
{
    var row,cell,str;
    row = document.getElementById("exhibitsTr").insertRow();
    if(row != null )
    {
        cell = row.insertCell();
        cell.align="center";
        cell.innerHTML="<input style=\"text-align:center;\" type=\"text\" name=\"ZP_NAME\" readonly=\"readonly\" value= \"\">";
        cell = row.insertCell();
        cell.align="center";
        cell.innerHTML="<input style=\"text-align:center;\" type=\"text\" name=\"ZP_PIC\" readonly=\"readonly\" value= \"\">";
        cell = row.insertCell();
        cell.align="center";
        cell.innerHTML="<input style=\"text-align:center;\" type=\"text\" name=\"ZP_DESCRIPTION\" readonly=\"readonly\" value= \"\">";
        cell = row.insertCell();
        cell.align="center";
        cell.id = randomChar(10);
        cell.innerHTML="<input type=\"button\" value=\"删除\" onclick=\'deleteitem(this);\'>";
        count++;
    }
}