Question

如何用JS实现自动求和（单价*数量）

<tr>
<td width="32%" height="0" align="center" class="td1"><strong>商品图片</strong></td>
<td width="26%" align="center" class="td1"><strong>商品名称</strong></td>
<td width="15%" align="center" class="td1"><strong>单价(￥)</strong></td>
<td width="14%" align="center" class="td1"><strong>数量</strong></td>
<td width="13%" align="center" class="td1"><strong>合计</strong></td>
</tr>

<tr>
<td align="center" class="td1"><img src="uploads/food/<?php echo $row[pictrue]?>" width="134" height="77" /></td>
<td align="center" class="td1 green" ><?php echo $row[mingcheng]?></td><input type='hidden' name='mingcheng_<?php echo $i?>' value="<?php echo $row[mingcheng]?>"/>
<td align="center" class="td1"><?php echo $row[jiage]?></td><input type='hidden' name='jiage_<?php echo $i?>' value="<?php echo $row[jiage]?>"/>
<td align="center" class="td1"><?php echo $_POST["num_".$i]?><input type='hidden' name='num_<?php echo $i?>' value="<?echo $_POST["num_".$i]?>"/></td>
<td align="center" class="td1 red"><?php echo $price?>￥<input type='hidden' name='sum_<?php echo $i?>' value="<?php echo $price?>"/></td>
<input type="hidden" name="num_<?php echo $i?>" value="<?php echo $_POST["num_".$i]?>">
</tr>

Answer 1

var pri = parseInt(document.getElementById('inpbox1').innerText);//单价
var num = parseInt(document.getElementById('inpbox2').innerText);//数量
alert(pri*num)//弹出单价*数量的合计

Answer 2

// using jquery
var items = $("tr");
var len = items.length;
for (var i = 0; i < len; i++) {
    var jiage = items.find("td>input#jiage_" + i).val();
    var num = items.find("td>input#num_" + i).val();
    var sum = jiage * num;
    $("input#sum_" + i).val(sum );
}

追问

这是JS代码还是PHP代码？

追答

jquery库实现的，js代码