尝试了多种方法，进行了大量研究（也许我错过了一些东西但无法完成）所以，我想知道是否可以对 html select 的选定值求和
这是我的代码
<select id="m4r1InfoMrP" name="m4r1InfoMrP">
<option value="1">1</option>
<option value="2">2</option>
<option value="4">4</option>
<option value="8">8</option>
</select>
还有另外一个
<select id="m4r1InfoMrS" name="m4r1InfoMrS" >
<option value="1">1</option>
<option value="2">2</option>
<option value="4">4</option>
<option value="8">8</option>
</select>
我的JS代码
<script type="text/javascript">
var m4r1InfoMrP = document.getElementById( "m4r1InfoMrP" ),
m4r1InfoMrPValue = m4r1InfoMrP.value;
var m4r1InfoMrS = document.getElementById( "m4r1InfoMrS" ),
m4r1InfoMrSValue = m4r1InfoMrS.value;
var sum = 0;
var a = m4r1InfoMrPValue;
var b = m4r1InfoMrSValue;
sum = a + b;
document.getElementById("m4r1InfoMrPS").value = sum;
</script>
我正在寻找的是对所选值求和并将其显示在 m4r1InfoMrPS 上
提前致谢
您需要使用change每个事件<select>元素。另外，您需要转换为数字以进行加法，如下所示。
var m4r1InfoMrP = document.getElementById("m4r1InfoMrP"),
m4r1InfoMrPValue = m4r1InfoMrP.value;
var m4r1InfoMrS = document.getElementById("m4r1InfoMrS"),
m4r1InfoMrSValue = m4r1InfoMrS.value;
m4r1InfoMrP.onchange = () => calculate();
m4r1InfoMrS.onchange = () => calculate();
function calculate() {
m4r1InfoMrPValue = m4r1InfoMrP.value;
m4r1InfoMrSValue = m4r1InfoMrS.value;
var sum = 0;
var a = +m4r1InfoMrPValue;
var b = +m4r1InfoMrSValue;
sum = a + b;
document.getElementById("m4r1InfoMrPS").value = sum;
}
calculate()
<select id="m4r1InfoMrP" name="m4r1InfoMrP">
<option value="1">1</option>
<option value="2">2</option>
<option value="4">4</option>
<option value="8">8</option>
</select>
<select id="m4r1InfoMrS" name="m4r1InfoMrS">
<option value="1">1</option>
<option value="2">2</option>
<option value="4">4</option>
<option value="8">8</option>
</select>
<input id="m4r1InfoMrPS" />
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
