如何删除输入javascript中数字的最后一位答案

【问题标题】：how to I remove the last digit of the number in input javascript如何删除输入javascript中数字的最后一位
【发布时间】：2019-04-01 05:15:28
【问题描述】：

   <!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>

<body>
<input id="txtBox" type="text" style="text-align: right;font-size:70px;width: 400px;height: 150px; font-family: bold;" />
<br />
<button onclick="Click(event)" id="clear" style="user-select: none; font-size:25px; width:98px ; height: 70px; font-family:bold;">C</button>
<button onclick="Click(event)" id="del" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">delete</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">+/-</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">+</button>

<br />

<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">1</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">2</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">3</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">-</button>

<br />

<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">4</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">5</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">6</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">*</button>

<br />

<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">7</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">8</button>
<button onclick="Click(event)" id="num" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">9</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">/</button>

<br />

<button onclick="Click(event)" id="zero" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">0</button>
<button onclick="Click(event)" id="ope" style="user-select: none;font-size:25px; width:98px ; height: 70px; font-family:bold;">.</button>
<button onclick="Click(event)" id="equalto" style="user-select: none;font-size:25px; width:200px ; height: 70px; font-family:bold;">=</button>

<script>
    var nums = document.getElementById("num")
    var operator = document.getElementById("ope")
    var textbox = document.getElementById("txtBox")
    var strng=document.getElementById("txtBox").value;

    function Click(e) {
        var but = e.target;
        if (but.innerText != "=") {
            textbox.value += but.innerText
        }
        else {
            textbox.value = eval(textbox.value)
        }
        if (but.innerText == "C") {
            textbox.value = ""
        }
        if(but.innerText=="delete"){
            textbox.value = textbox.value.substring(0, textbox.value.length - 1);
        }
    }
</script>
</body>

</html>

我的家庭作业是做一个计算器，我一直在做很多事情。我只放了一个按钮，否则很难阅读代码。我只知道（函数、变量、if、else、while 和文档）我不能只删除最后一个数字，我需要一个只输出一个点的代码（如 0.555）。有人可以帮我吗？

【问题讨论】：

你能举个例子，你到底想要什么？
@AbhishekMani 我想要的主要是，当使用计算器时，您可以输入错误的数字，我需要一个像退格键这样的按钮来删除它。哪个是最后一个(if(but.innerText=="delete")) 那行不通((
这到底是怎么回事？（它几乎肯定不会这样做）textbox.value = eval(textbox.value)
@NarminMustafali 检查我的解决方案是否有效，您可以创建一个从 0 到长度 -1 的子字符串，从而删除最后一个字符
@AbhishekMani 例如我写了 "255" 并点击 "delete" ，它输出 "255delet" 。它删除按钮名称的最后一个字符

标签： javascript function button calculator string-length

【解决方案1】：

你只需要在你的代码中更新这个，

 if (but.innerText != "=" && but.innerText != "delete") {
        textbox.value += but.innerText
    }

your solution

【讨论】：