<form name="messageForm">
<div class="refitem">
币种:<select onchange="outputRst()" id="sMoney">
<option>请选择..</option>
<option>美元</option>
<option>人民币</option>
<option>英镑</option>
<option>日元</option>
</select>
金额<input type="text" id="amount" onchange="outputRst()" />
</div>
<br /><br />
<table id="tbRst" border="1">
<tr><td>币种</td><td>兑换金额</td><td>汇率</td></tr>
</table>
</form>
<script>
var rate = { 美元: { 人民币: 6.5781, 英镑: 0.6943, 日元: 119.53,美元:1 } };//参考对照
var Money = ',美元,人民币,英镑,日元,';
var tbRst = document.getElementById('tbRst'), tr,td;
var refMoney, refAmount, tMoney, tAmount, tRate;
var sel = document.getElementById('sMoney');
function outputRst() {
//移除上一次的转换
while (tbRst.rows.length > 1) { tr = tbRst.rows[tbRst.rows.length - 1]; tr.parentNode.removeChild(tr); }
if (sel.selectedIndex == 0) return;
refMoney = sel.options[sel.selectedIndex].text;//参考币种
refAmount = parseFloat(document.getElementById('amount').value) || 0;//数量
var arr = Money.replace(',' + refMoney + ',',',').replace(/^,|,$/g, '').split(',');//删除参考币种后拆分得到目标币种
for (var i = 0; i < arr.length; i++) {
tMoney = arr[i];
if (refMoney == '美元') tRate = rate.美元[tMoney];//美元,有参考值可取,不需要计算
else tRate = 1 / rate.美元[refMoney] * rate.美元[tMoney]; //不是美元,需要重新换算汇率
tr = tbRst.insertRow(tbRst.rows.length);
td = tr.insertCell(0); td.innerHTML = tMoney;
td = tr.insertCell(1); td.innerHTML = (tRate * refAmount).toFixed(2);
td = tr.insertCell(2); td.innerHTML = tRate.toFixed(4);
}
}
</script>