运算器.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>计算器</title>
</head>
<body>
<input type="text" id="num1"/>
<input type="text" id="opt"/>
<input type="text" id="num2"/>=
<input type="text" id="result"/>
<input type="button" id="comp" value="运算" />
<script type="text/javascript">
var comp = document.getElementById("comp");
comp.onclick = function(){
var num1= Number(document.getElementById("num1").value);
var num2 = Number(document.getElementById("num2").value);
var opt = document.getElementById("opt").value;
var result;
switch(opt){
case "+":
result = num1 + num2;
break;
case "-":
result = num1 - num2;
break;
case "*":
result = num1 * num2;
break;
case "/":
result = num1 / num2;
break;
}
document.getElementById("result").value=result;
}
</script>
</body>
</html>