<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var txt1 = document.getElementById("txt1").value;
var txt2 = document.getElementById("txt2").value;
var c= document.getElementById("select").value;
var result = "";
switch(c) {
case "+":
result = parseInt(txt1) + parseInt(txt2);
break;
case "-":
result = parseInt(txt1) - parseInt(txt2);
break;
case "*":
result = parseInt(txt1) * parseInt(txt2);
break;
default:
result = parseInt(txt1) / parseInt(txt2);
}
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=' = ' onclick='count();' />
<input type='text' id='fruit'/>
</body>
</html>
count()函数没有了后面的“}”
onclick="count()"后面不能有分号以及count()函数少了一个}