<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>計算器</title>
<script type="text/javascript">
window.onload = function(){
var oInput01 = document.getElementById('input01');
var oInput02 = document.getElementById('input02');
var oSelect = document.getElementById('select');
var oBtn = document.getElementById('btn');
oBtn.onclick = function(){
var val01 = oInput01.value;
var val02 = oInput02.value;
//不做此判斷會彈出“NaN”
if(val01==""?||?val02==""){
alert('輸入框不能為空！');
return;
}
if(isNaN(val01)?||?isNaN(val02)){
alert('請輸入數字！');
return;
}
switch(oSelect.value){
case?'0':
alert((parseFloat(val01)*100?+?parseFloat(val02)*100)/100);
break;
case?'1':
alert((parseFloat(val01)*100?-?parseFloat(val02)*100)/100);
break;
case?'2':
alert((parseFloat(val01)*100)?*?(parseFloat(val02)*100)/10000);
break;
case?'3':
alert((parseFloat(val01)*100)?/?(parseFloat(val02)*100));
break;
}
}
}
</script>
</head>
<body>
<h1>計算器</h1>
<input type="text" name="" id="input01" />
<select id="select">
<option value="0">+</option>
<option value="1">-</option>
<option value="2">*</option>
<option value="3">/</option>
<lect>
<input type="text" name="" id="input02" />
<input type="button" name="" value="計算" id="btn" />
</body>
<html>
