计算器
<!DOCTYPE html>
<html>
<head>
<title>计算器</title>
<script type="text/javascript">
window.onload = function(){
var txt1 = document.getElementById("txt1");
var txt2 = document.getElementById("txt2");
var select1 = document.getElementById("select");
var btn = document.getElementById("btn");
var btn1 = document.getElementById("btn1");
btn.onclick = function(){
var val1 = txt1.value;
var val2 = txt2.value;
if (val1=="" || val2=="") {
alert("输入的内容不能为空！请重新输入:");
return;
}
if (isNaN(val1) || isNaN(val2)) {
alert("请输入数字！");
return;
}
switch(select1.value){
case "0":
alert((parseFloat(val1)*100 + parseFloat(val2)*100)/100)
break
case "1":
alert((parseFloat(val1)*100 - parseFloat(val2)*100)/100)
break
case "2":
alert((parseFloat(val1)*100 * parseFloat(val2)*100)/10000)
break
case "3":
alert((parseFloat(val1)*100 / parseFloat(val2)*100)/100)
break
}
}
btn1.onclick = function(){
txt1.value = "";
txt2.value = "";
}
}
</script>
</head>
<body>
<h1>计算器</h1>
<input type="text" name="" id="txt1">
<select id="select">
<option value="0">+</option>
<option value="1">-</option>
<option value="2">*</option>
<option value="3">/</option>
</select>
<input type="text" name="" id="txt2">
<input type="button" name="" value="计算" id="btn">
<input type="button" name="" value="清除" id="btn1">
</body>
</html>
