<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title> 事件</title>
<script type="text/javascript">
//使用parseInt()函数可解析一个字符串,并返回一个整数。
function count(){
var t1 = document.getElementById("txt1").value;
var t2 = document.getElementById("txt2").value;
var zahuishi = document.getElementById("select").value;
var why;
switch(zahuishi){
case "+":
why = parseInt(t1) + parseInt(t2);
case "-":
why = parseInt(t1) - parseInt(t2);
case "*":
why = parseInt(t1) * parseInt(t2);
default:
why = parseInt(t1) / parseInt(t2);
}
document.getElementById("fruit").value= why;
}
// function count(){
// var oTxt1 = document.getElementById("txt1").value;
// var oTxt2 = document.getElementById("txt2").value;
// var oSlt = document.getElementById("select").value;
// var result = "";
// switch(oSlt) {
// case "+":
// result = parseInt(oTxt1) + parseInt(oTxt2);
// break;
// case "-":
// result = parseInt(oTxt1) - parseInt(oTxt2);
// break;
// case "*":
// result = parseInt(oTxt1) * parseInt(oTxt2);
// break;
// default:
// result = parseInt(oTxt1) / parseInt(oTxt2);
// }
// 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() /> <!--通过 = 按钮来调用创建的函数，得到结果-->
<input type='text' id='fruit' />
</body>
</html>
switch(zahuishi){
case "+":
why = parseInt(t1) + parseInt(t2);
break;
case "-":
why = parseInt(t1) - parseInt(t2);
break;
case "*":
why = parseInt(t1) * parseInt(t2);
break;
default:
why = parseInt(t1) / parseInt(t2);
}
document.getElementById("fruit").value= why;
}
//原来是没有break;