我必须用HTML编写一个计算器。我真的找不到出错的地方，也没有显示出结果。我找不到有什么问题你能帮忙吗？我在Chrome中运行它。
JavaScript文件和HTML：
showresult(choise){
var n1=parsefloat(document.getElementById('num1').value);
var n2=parsefloat(document.getElementById('num2').value);
var r;
var c=choise;
switch(c)
{
case '1':
r=n1+n2;
break;
case '2':
r=n1-n2;
break;
case '3':
r=n1*n2;
break;
case '4':
r=n1/n2;
break;
case '5':
r=n2*100/n1;
break;
default:
break;
}
document.getElementById('result').innerHTML=r;
}<!DOCTYPE html>
<html>
<head>
<title>Calculator</title>
<script src="calculator.js" type="text/javascript"></script>
</head>
<body>
<h1>My calculator</h1>
<table border="1" cellpadding="5" cellspacing="5" width="600">
<tr align="center">
<td>First number</td>
<td>Second Number</td>
<td>Result</td>
</tr>
<tr align="center">
<td><input name="number1" type="text" size=10 id='num1'/></td>
<td><input name="number2" type="text" size=10 id='num2'/></td>
<td> <input type="text" id='result' readonly ></td>
</tr>
<tr>
<td colspan="3">
<button onclick="showresult('1')">+</button>
<button onclick="showresult('2')">-</button>
<button onclick="showresult('3')">*</button>
<button onclick="showresult('4')">/</button>
<button onclick="showresult('5')">%</button>
</td>
</tr>
</table>
</body>
</html>
答案 0 :(得分：1)
要解决的问题：
1）在引用value元素时，分配给innerHTML，而不是input。 （他们没有内容，因此没有innerHTML。
2）使用关键字function启动函数声明。
3）它是parseFloat，而不是parsefloat。 JavaScript区分大小写。
最小化代码：
function showresult(choise){
var n1=parseFloat(document.getElementById('num1').value);
var n2=parseFloat(document.getElementById('num2').value);
var r;
var c=choise;
switch(c)
{
case '1':
r=n1+n2;
break;
case '2':
r=n1-n2;
break;
case '3':
r=n1*n2;
break;
case '4':
r=n1/n2;
break;
case '5':
r=n2*100/n1;
break;
default:
break;
}
document.getElementById('result').value=r;
}<!DOCTYPE html>
<html>
<head>
<title>Calculator</title>
<script src="calculator.js" type="text/javascript"></script>
</head>
<body>
<h1>My calculator</h1>
<table border="1" cellpadding="5" cellspacing="5" width="600">
<tr align="center">
<td>First number</td>
<td>Second Number</td>
<td>Result</td>
</tr>
<tr align="center">
<td><input name="number1" type="text" size=10 id='num1'/></td>
<td><input name="number2" type="text" size=10 id='num2'/></td>
<td> <input type="text" id='result' readonly ></td>
</tr>
<tr>
<td colspan="3">
<button onclick="showresult('1')">+</button>
<button onclick="showresult('2')">-</button>
<button onclick="showresult('3')">*</button>
<button onclick="showresult('4')">/</button>
<button onclick="showresult('5')">%</button>
</td>
</tr>
</table>
</body>
</html>
答案 1 :(得分：0)
确保正确声明该功能。
function showresult(choise) {
/* ... */
}
另外，请记住Javascript区分大小写，因此解析float的正确方法是
parseFloat()
最后，正如gillesc所指出的，在输入元素上使用属性value。
document.getElementById('result').value=r;
答案 2 :(得分：0)
您应该在代码中将“ innerHTML”替换为“value”。
如果要访问非输入HTML元素中的文本，那么您将不得不使用innerHTML属性而不是值
现在代码变为：
document.getElementById('result').value=r;
这里我们使用了value属性，所有输入元素都必须使用它来获取用户输入的值。
答案 3 :(得分：0)
您可以在代码中使用此功能
function calc(form) {
var D = "0";
var A = document.getElementById("num1").value;
var B = document.getElementById("op").value;
var C = document.getElementById("num2").value;
switch(B){
case'+':
D= parseInt(A)+parseInt(C); break;
case'-':
D= parseInt(A)-parseInt(C); break;
case'*':
D=parseInt(A)*parseInt(C); break;
case'/':
D=parseInt(A)/parseInt(C); break;
}
}
答案 4 :(得分：0)
<script>
var num1;
var op;
function pressBtn(value){
var prev = document.forms["calc"]["display"].value;
if (!(prev == "" && value==0)){
var newval = prev+value;
document.forms["calc"]["display"].value = newval;
}
}
function pressOP(operator){
op = operator;
var display = document.forms["calc"]["display"].value;
num1 = parseInt(display);
document.forms["calc"]["display"].value = "";
}
function pressEq(){
var display = document.forms["calc"]["display"].value;
var num2 = parseInt(display);
switch(op){
case "P":
var ans=num1+num2;
break;
case "M":
var ans=num1-num2;
break;
}
document.forms["calc"]["display"].value = ans;
}
</script><style>
input[type=button]{
width: 100px;
height: 100px;
font-size: 36px;
margin: 5px;
}
input[type=text]{
width: 300px;
height: 75px;
font-size: 48px;
margin: 5px;
text-align: right;
}
</style><body style="background: #ccc;">
<div style="width: 500px; margin: auto; background: #fff; text-align: center">
<form name="calc">
<input type="text" name="display" readonly ><br>
<input type="button" name="btn7" value="7" onClick="pressBtn(7)">
<input type="button" name="btn8" value="8" onClick="pressBtn(8)">
<input type="button" name="btn9" value="9" onClick="pressBtn(9)"><br>
<input type="button" name="btn4" value="4" onClick="pressBtn(4)">
<input type="button" name="btn5" value="5" onClick="pressBtn(5)">
<input type="button" name="btn6" value="6" onClick="pressBtn(6)"><br>
<input type="button" name="btn1" value="1" onClick="pressBtn(1)">
<input type="button" name="btn2" value="2" onClick="pressBtn(2)">
<input type="button" name="btn3" value="3" onClick="pressBtn(3)"><br>
<input type="button" name="btn0" value="0" onClick="pressBtn(0)">
<input type="button" name="btnPlus" value="+" onClick="pressOP('P')" >
<input type="button" name="btnPlus" value="-" onClick="pressOP('M')" ><br>
<input type="button" name="btnEq" value="=" onClick="pressEq();" >
</form>
</div>
</body>
答案 5 :(得分：0)
var cnum = document.getElementsByClassName('c-num')[0];
var cope = document.getElementsByClassName('c-operator')[0];
var intom = document.getElementById('intop');
var inbottom = document.getElementById('inbottom');
var newinbottom;
var newinbottom2;
var sign;
for(i=0;i<10;i++){
cnum.innerHTML +='<span class="numb" value="'+i+'" id="numid'+i+'" onclick="puton('+i+')">'+i+'</span>';
}
document.getElementById('numid0').style.order = "1";
function puton(numb){
inbottom.value += numb
}
function ans(answer){
//console.log(sign)
if(inbottom.value ==''){
alert('type input');
}else if(sign == "plus"){
newinbottom2 = inbottom.value;
intom.value = inbottom.value;
inbottom.value = parseInt(newinbottom) + parseInt(newinbottom2);
}else if(sign == "minus"){
newinbottom2 = inbottom.value;
intom.value = inbottom.value;
inbottom.value = newinbottom - newinbottom2;
}else if(sign == "divi"){
newinbottom2 = inbottom.value;
intom.value = inbottom.value;
inbottom.value = newinbottom / newinbottom2;
}else if(sign == "mul"){
newinbottom2 = inbottom.value;
intom.value = inbottom.value;
inbottom.value = newinbottom * newinbottom2;
}
sign ='';
}
function opr(opra){
if(sign != '' && sign != undefined){
ans();
}
else if(opra == "clr"){
intom.value =''
inbottom.value ='';
newinbottom='';
newinbottom='';
sign ='';
}
else if(opra == "plus"){
newinbottom = inbottom.value;
intom.value = inbottom.value;
inbottom.value = '';
sign = "plus";
}else if(opra == "minus"){
newinbottom = inbottom.value;
intom.value = inbottom.value;
inbottom.value = '';
sign = "minus";
}else if(opra == "divi"){
newinbottom = inbottom.value;
intom.value = inbottom.value;
inbottom.value = '';
sign = "divi";
}else if(opra == "mul"){
newinbottom = inbottom.value;
intom.value = inbottom.value;
inbottom.value = '';
sign = "mul";
}
}
.main{
width:100vw;
height: 100vh;
display: flex;
justify-content: center;
}
.c-body {
width: 400px;
height: 255px;
background: #ccc;
border: 1px solid;
}
.c-num{
width: 100%;
display: flex;
flex-wrap: wrap;
}
.c-operator{
flex-shrink: 1;
display: flex;
flex-wrap: wrap;
flex-direction: column;
}
.c-row{
display: flex;
flex-flow: row;
}
.c-operator [id^='numid']{
width: 90px;
flex-direction: initial;
}
[id^='numid'] {
display: flex;
flex-shrink: 1;
background: #fff;
padding: 4px;
margin: 4px;
width: 80px;
justify-content: center;
cursor: pointer;
flex-direction: inherit;
}
.c-minputs .inbox{
display: block;
width: 100%;
}
[id^='numid']:hover{
background: #f5f5f5;
}<div class="main">
<div class="c-body">
<div class="c-minputs">
<input id="intop" type="number" class="topin inbox" disabled>
<input id="inbottom" type="number" class="bottomin inbox" placeholder="Type Here">
</div>
<div class="c-row">
<div class="c-num">
</div>
<div class="c-operator">
<span class="numb" id="numidplus" onclick="opr('plus')">+</span>
<span class="numb" id="numidminus" onclick="opr('minus')">-</span>
<span class="numb" id="numiddiv" onclick="opr('divi')">/</span>
<span class="numb" id="numidmul" onclick="opr('mul')">*</span>
<span class="numb" id="numidans" onclick="ans('answer')">=</span>
<span class="numb" id="numidclr" onclick="opr('clr')">c</span>
</div>
</div>
</div>
</div>
答案 6 :(得分：0)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>stackoverflow</title>
<style>
body{
background: linear-gradient(90deg, rgba(2,0,36,1) 0%, rgba(9,9,121,1) 35%, rgba(0,212,255,1) 100%);
}
.button {
box-shadow: 0px 10px 14px -7px #276873;
background: linear-gradient(to bottom, #599bb3 5%, #408c99 100%);
background-color: #599bb3;
border-radius: 4px;
border: 1px solid #29668f;
display: inline-block;
cursor: pointer;
color: #ffffff;
font-family: Arial;
font-size: 25px;
font-weight: bold;
padding: 21px 6px;
text-decoration: none;
text-shadow: 0px 1px 0px #3d768a;
height: 50px;
width: 80px;
padding: 0px;
}
.button:hover {
background:linear-gradient(to bottom, #408c99 5%, #599bb3 100%);
background-color:#408c99;
}
form>input{
height: 40px;
width: 329px;
border-radius: 4px;
border: none;
margin-left: 500px;
font-size: 30px;
}
table{
margin-left: 500px;
}
</style>
</head>
<body>
<div id="main">
<form name="form">
<input name="textview">
</form>
<table>
<tr>
<td><input type="button" class="button" value="Clear" onClick="c()"></td>
</tr>
<tr>
<td><input type="button" class="button" value="7" onClick="insert(7)"></td>
<td><input type="button" class="button" value="8" onClick="insert(8)"></td>
<td><input type="button" class="button" value="9" onClick="insert(9)"></td>
<td><input type="button" class="button" value="/" onClick="insert('/')"></td>
</tr>
<tr>
<td><input type="button" class="button" value="4" onClick="insert(4)"></td>
<td><input type="button" class="button" value="5" onClick="insert(5)"></td>
<td><input type="button" class="button" value="6" onClick="insert(6)"></td>
<td><input type="button" class="button" value="-" onClick="insert('-')"></td>
</tr>
<tr>
<td><input type="button" class="button" value="1" onClick="insert(1)"></td>
<td><input type="button" class="button" value="2" onClick="insert(2)"></td>
<td><input type="button" class="button" value="3" onClick="insert(3)"></td>
<td><input type="button" class="button" value="+" onClick="insert('+')"></td>
</tr>
<tr>
<td><input type="button" class="button" value="0" onClick="insert(0)"></td>
<td><input type="button" class="button" value="." onClick="insert('.')"></td>
<td><input type="button" class="button" value="=" onClick="equal('=')"></td>
<td><input type="button" class="button" value="*" onClick="insert('*')"></td>
</tr>
</table>
</div>
<script>
function insert(num){
document.form.textview.value = document.form.textview.value+num;
}
function equal(){
let exp = document.form.textview.value;
if(exp){
document.form.textview.value = eval(exp)
}
else{
console.log('Something Wrong')
}
}
function c(){
document.form.textview.value = null;
}
</script>
</body>
</html>