<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var num1 = parsefloat(document.getElementById("txt1").value);
var num2 = parsefloat(document.getElementById("txt2").value);
var sel = document.getElementById("select").value;
var result ;
switch(sel){
case "+" :
result = num1 + num2;
break;
case "-" ：
result = num1 - num2;
break;
case "*" :
result = num1 * num2;
break;
default :
result = num1 / num2;
;
}
document.getElementById("fruit").value=result;
}
</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-->
<input type='text' id='fruit' />
</body>
</html>
swith里的第二个case的冒号是中文的冒号