单击等于按钮无结果-慕课网

首页课程实战体系课手记专栏慕课教程

单击等于按钮无结果

来源：6-11 编程练习

慕桂英0114709

2018-07-17 22:24

<!DOCTYPE html>

<html>

<head>

function count(){

//获取第一个输入框的值

var a = document.getElementById("txt1").value;

//获取第二个输入框的值

var b = document.getElementById("txt2").value;

//获取选择框的值

var c = document.getElementById("select").value;

//获取通过下拉框来选择的值来改变加减乘除的运算法则

var result;

a = parseInt(a);

b = parseInt(b);

switch c

{

case "+":

result = a+b;

break;

case "-":

result = a-b;

break;

case "*":

result = a*b;

break;

case "/":

result = a/b;

break;

default:

result = 0;

}

//设置结果输入框的值

document.getElementById("fruit").value = result;

}

</script>

</head>

<body>

</select>

</body>

</html>

写回答关注

3回答

慕仔4922981

2018-07-21 15:10:41

看了下你的代码，没有问题，拷贝一份运行，也没问题，除法加个除数的判0就好了

0 0
慕设计2549849

2018-07-20 08:47:51
<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){

//获取第一个输入框的值
var num1=document.getElementById("txt1").value;
//获取第二个输入框的值
var num2=document.getElementById("txt2").value;
//获取选择框的值
var mycount=document.getElementById("select").value;
//获取通过下拉框来选择的值来改变加减乘除的运算法则
//设置结果输入框的值
switch(mycount){
case "+":
document.getElementById("fruit").value=parseInt(num1)+parseInt(num2);
break;
case "-":
document.getElementById("fruit").value=parseInt(num1)-parseInt(num2);
break;
case "*":
document.getElementById("fruit").value=parseInt(num1)*parseInt(num2);
break;
case "/":
document.getElementById("fruit").value=parseInt(num1)/parseInt(num2);
break;
}
}
</script>
</head>
<body>
<input type='text' id='txt1' />
<select id='select'>
<option value='+'>+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type='text' id='txt2' />
<input type='button' value=' = ' onclick="count()" />

<input type='text' id='fruit' />
</body>
</html>
0 0
慕焚

2018-07-18 10:37:23

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var x = document.getElementById('txt1').value;
//获取第一个输入框的值
var y = document.getElementById('txt2').value;
//获取第二个输入框的值
var z = document.getElementById('select').value;

//获取选择框的值
switch (z) {
case '+': f = parseInt(x)+parseInt(y);break;
case '-': f = parseInt(x)-parseInt(y);break;
case '*': f = parseInt(x)*parseInt(y);break;
case '/': f = parseInt(x)/parseInt(y);break;
//获取通过下拉框来选择的值来改变加减乘除的运算法则
}
//设置结果输入框的值
document.getElementById('fruit').value = f
}
</script>
</head>
<body>
<input type='text' id='txt1' />
<select id='select'>
<option value='+'>+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type='text' id='txt2' />
<input type='button' value=' = ' onclick="count()"/> 
<input type='text' id='fruit' />
</body>
</html>

0 0