function checkSum()
{
var sum = 0
for(var i=0i<document.form1.elements["writer"].lengthi++)
{
if(document.form1.elements["writer"][i].checked)
{
sum = sum +parseInt(document.form1.elements["writer"][i].value)
}
}
totalprice.innerText = sum +" 元"
}
</script>
<form method=post name=form1>
<input type="checkbox" name=writer value="34" onclick="checkSum()">韩国耳饰tm56（34元）<br>
<input type="checkbox" name=writer value="46" onclick="checkSum()">纯银吊坠tc34（46元）<br>
<input type="checkbox" name=writer value="30" onclick="checkSum()">黄莺手镯ta345（30元）<br>
<input type="checkbox" name=writer value="40" onclick="checkSum()">翡翠玉镯1346（40元）<br>
<input type="checkbox" name=writer value="50" onclick="checkSum()">天涯耳饰1233（50元）<br>
<br>
总价为：<span id="totalprice">0 元</span>
</form>
楼主是想要点击合计就是出数值还是什么？如果说点击合计就算出值的话如下
<table width="400" border="1"><tr>
<th rows="5">简易购物车</th>
</tr>
<tr>
<td>商品名称</td>
<td>数量(件)</td>
<td>单价(美元)</td>
<td>运费(美元)</td>
<td><button onclick="fun()">合计</button></td>
</tr>
<tr>
<td><input type="text" name="goodsName" /></td>
<td><input type="text" name="num" id="num" /></td>
<td><input type="text" name="price" id="price" /></td>
<td><input type="text" name="freight" id="freight" /></td>
<td><input type="text" name="total" id="total" /></td>
</tr>
</table>
<script>
function fun(){
var num = document.getElementById("num").value
var price = document.getElementById("price").value
var freight = parseInt(document.getElementById("freight").value)
var total = (price * num) + freight
document.getElementById("total").value = total
}
</script>
