表格动态添加删除一行

<script language=javascript>allCount=1function addline(){newRow=listtable.insertRow(listtable.rows.length);newRow.ln=allCount;newRow.id="line"+allCount;addRowCells(newRow);allCount++}function insertline(lineid){for(i=0;i<listtable.rows.length;i++){   if(listtable.rows[i].id==lineid.id){    newRow=listtable.insertRow(i);    newRow.ln=allCount;    newRow.id="line"+allCount;    addRowCells(newRow);    allCount++    return;   }}}function delline(lineid){for(i=0;i<listtable.rows.length;i++){    if(listtable.rows[i].id==lineid.id){     listtable.deleteRow(i);     return;    }}}function addRowCells(row){c1=row.insertCell(0);c1.bgColor="#FFFFFF";c1.innerHTML="<input size=10 name=sClass"+allCount+">";c2=row.insertCell(1);c2.bgColor="#FFFFFF";c2.innerHTML="<input size=10 name=sMaterial"+allCount+">";c3=row.insertCell(2);c3.bgColor="#FFFFFF";c3.innerHTML="<input size=10 name=sSpec"+allCount+">";c4=newRow.insertCell(3);c4.bgColor="#FFFFFF";c4.align="CENTER";c4.innerHTML="<input type=button value=删除 onclick=delline(line"+allCount+")>";c4.innerHTML+="<input type=button value=插入 onclick=insertline(line"+allCount+")>";}</script>-------------------------------------------------------------------------------------<table width=400 height="20" border="1" align="center" cellpadding=0 cellspacing=0 id=listtable>   <tr align=center height=20>   <td bgcolor=#FFFFFF><b>品名</b></td>   <td bgcolor=#FFFFFF><b>材质</b></td>   <td bgcolor=#FFFFFF><b>规格</b></td>   <td bgcolor=#FFFFFF><b><a href="#" onclick="addline()" style="text-decoration:none;">+</a></b></td>   </tr></table>