<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var s="";
var a = document.getElementById("txt1").value;
//获取第一个输入框的值
var b = document.getElementById("txt2").value;
//获取第二个输入框的值
var sel = document.getElementById("select").value;
//获取选择框的值
//获取通过下拉框来选择的值来改变加减乘除的运算法则
a=parseInt(a);
b=parseInt(b);
switch(sel)
{
case "+":
s = a + b;
case "-":
s = a - b;
case "*":
s = a * b;
case "/":
s = a / b;
}
document.getElementById("fruit").value = s;
//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=' = ' onlick="count()"/> <!--通过 = 按钮来调用创建的函数,得到结果-->
Hardy丶
慕的地6079101
qq_狼烟四起_0
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