<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var num1 = parseInt(document.getElementById('txt1').value);
//获取第一个输入框的值
var num1 = parseInt(document.getElementById('txt2').value);
//获取第二个输入框的值
var cal = document.getElementById('select');
//获取选择框的值
var result = '';
switch (cal) {
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
result = num1 / num2;
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
document.getElementById('fruit').value = result;
//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>
//请大家麻烦帮忙检查一下这段代码哪里错了……
