<table width=300 height=100 border=0 align="center" cellspacing=0 cellpadding=0>
 <tr>
  <td rowspan=3>例子</td>
  <td>选项一</td>
 </tr>
 <tr>
  <td>选项二</td>
 </tr>
 <tr>
  <td>选项三</td>
 </tr>
</table>

------解决方案--------------------
用rowspan

------解决方案--------------------
<style>
.td_blue{background-color:#3982F7;}
</style>

<table id="tableId" name="tableId" align="center" cellpadding="2" cellspacing="1" width="300" class="border3" border="2" >
	
  <tr>
	<td align="left" class="color9" id="cor_1"  colspan="2" rowSpan="1" height="43" width="50%" onclick="selTD(11);sel(1);">111</td>
	<td align="left" class="color9" id="cor_2"  colspan="2" rowSpan="1" height="43" width="50%" onclick="selTD(21);sel(2);">222</td>
	</tr>
	<tr>	
	<td align="left" class="color9" id="cor_3" colspan="2"  rowSpan="1" height="43" width="50%" onclick="selTD(12);sel(3);">333</td>
	<td align="left" class="color9" id="cor_4" colspan="2"  rowSpan="1" height="43" width="50%" onclick="selTD(22);sel(4);">444</td>

	</tr>
	<tr>	
	<td align="left" class="color9" id="cor_5" colspan="2" rowSpan="1" height="43" width="50%" onclick="selTD(13);sel(5);">555</td>
	<td align="left" class="color9" id="cor_6" colspan="2" rowSpan="1" height="43" width="50%" onclick="selTD(23);sel(6);">666</td>

	</tr>
		</table>
<p align="center"><input type="button" value="合并" onclick="selTD('join');sel(7);"></p> 
<script>
function sel(i){

x=document.getElementById('cor_'+i)
if(i!=7){x.className="td_blue"}
}

var td_array=new Array();
var flag='td_flag';
var tdcol1="",tdcol2="",tdrow1="",tdrow2="";
function selTD(i)
{ 
	   i=i.toString();
	   if(flag!="td_flag"&&i!='join'){
	   tdcol2=i.substr(0,1)
      tdrow2=i.substr(1,1)
	   }
	   if(flag=='td_flag'&&i!='join'){ 
	   tdcol1=i.substr(0,1)
	   tdrow1=i.substr(1,1)
      flag=i
	   }

      if(i=="join"){

	   doTab(tdcol1,tdcol2,tdrow1,tdrow2);
	   flag='td_flag';

	   }

}

function doTab(tdcol1,tdcol2,tdrow1,tdrow2){
	
	if(tdcol1>tdcol2) {var temp=tdcol1;
		               tdcol1=tdcol2;
					   tdcol2=temp;
	                    }
	if(tdrow1>tdrow2) {var temp=tdrow1;