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我正在制作这个 Javascript 计算器，但我不知道如何让计算器解决 5-(3+1)、5-3+1 之类的问题。它只打印等式的 5-3 部分而不是 +1 这是我的代码：

<html>
<script>
function calc()
{
var D = "";
var A = document.getElementById("num1").value;
var B = document.getElementById("op").value;
var C = parseInt(document.getElementById("num2").value);
if(B == "+")
{
    D = parseInt(A)+parseInt(C);
}
else if(B == "-")
{
    D = parseInt(A)-parseInt(C);
}
else if(B == "*")
{
    D = parseInt(A)*parseInt(C);
}
else if(B == "/")
{
    D = parseInt(A)/parseInt(C);
}
else
{
    alert("Error")
}
document.getElementById("result").value = parseInt(D);
}
function conteq()
{
var D = document.getElementById("result").value;
var E = "";
document.getElementById("num1").value = D;
document.getElementById("op").value = E;
document.getElementById("num2").value = E;
    document.getElementById("result").value = E;
}
function resetcalc()
{
    var E = "";
    document.getElementById("num1").value = E;
    document.getElementById("op").value = E;
    document.getElementById("num2").value = E;
    document.getElementById("result").value = E;
}
</script>

<body>
<table align="center">
<td>This is a basic Javascript Calculator.<br /></td></table>
<table align="center"><td>(Number 1)<input type="text" id="num1" align="middle" name="num1" />
</td>
<table align="center"><td>(Operator)<input type="text" align="middle" id="op" name="op" /></td>    </table>
<table align="center"> <td>(Number 2)<input type="text" align="middle" id="num2" name="num2" /></td>  </table>
<table align="center"> <td><input type="button" align="middle" value="=" onClick="calc()" /></td>    </table>
<table align="center"><td>(Result)<input type="text" id="result" name="result" readonly />
</td></table>

<table align="center"><td><input type="button" value="Set Answer to Number 1" onClick="conteq()"    /></td></table>
<table align="center"><td><input type="button" value="Reset" onClick="resetcalc()" /></td></table>
</table>
</p>
</body>
</html>
4

1 回答 1

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您正在尝试将 ( 转换为整数，但不能（因为它不是）：

function calc()
{
    var D = "";
    var A = document.getElementById("num1").value;
    var B = document.getElementById("op").value;
    var C = document.getElementById("num2").value;

    D = eval(A + B + C);


    document.getElementById("result").value = D;
}
于 2013-04-17T14:34:22.697 回答