为什么我点等号没有结果的
慕雪4366338
2020-12-23 17:38
<!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 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");
//获取通过下拉框来选择的值来改变加减乘除的运算法则
switch (c) {
case "+":
document.getElementById("fruit").value = parseInt(a)+parseInt(b);
break;
case "-":
document.getElementById("fruit").value = parseInt(a)-parseInt(b);
break;
case "*":
document.getElementById("fruit").value = parseInt(a)*parseInt(b);
break;
case "/":
document.getElementById("fruit").value = parseInt(a)/parseInt(b);
break;
//设置结果输入框的值
}
</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()" /> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type='text' id='fruit' />
</body>
</html>
4回答
-
- 一只小白鼠i
- 2021-04-06 11:25:17
<!DOCTYPE html>
<html>
<head>
<title> 事件 </title>
<script type = "text/javascript" >
function count() {
var a = document.getElementById("txt1").value;
var b = document.getElementById("txt2").value;
var sum = 0;
//获取第一个输入框的值
//获取第二个输入框的值
//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
switch(c) {
case "+":
sum = parseInt(a)+ parseInt(b);
break;
case "-":
sum = parseInt(a) - parseInt(b);
break;
case "*":
sum = parseInt(a) * parseInt(b);
break;
case "/":
sum =parseInt(a) / parseInt(b);
break;
}
document.getElementById("fruit").value=sum;
}
</script>
</head>
<body>
<input type = 'text'id = 'txt1' / >
<select id = 'select' onchange="count()">
<option value = '+' > + < /option>
<option value = "-" > - < /option>
<option value = "*" > * < /option>
<option value = "/" > /</option >
</select>
<input type = 'text'id = 'txt2' / >
<input type = 'button'value = ' = 'onclick="count()" / >
<!--通过 = 按钮来调用创建的函数，得到结果-->
<input type = 'text'id = 'fruit' / >
</body>
</html>
-
- qq_默默_9
- 2021-01-25 10:53:44
海军与我正解
-
- 慕移动1082948
- 2020-12-28 20:31:43
var c = document.getElementById("select");
这里应该是
var c = document.getElementById("select").value;
-
- 慕雪4366338
- 2020-12-23 17:38:39
有没有大哥看看有什么问题的???
JavaScript进阶篇
468192 学习 · 21891 问题
相似问题