我有个更好的，你试一试，可惜我这个是HTML格式的：：很好用：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>网页特效|网页特效代码()---普通计算器代码</title>
</head>
<body>
<script language="JavaScript">
<!-- Hide the script from old browsers --
function compute(obj)
{obj.expr.value = eval(obj.expr.value)}
var one = '1'
var two = '2'
var three = '3'
var four = '4'
var five = '5'
var six = '6'
var seven = '7'
var eight = '8'
var nine = '9'
var zero = '0'
var plus = '+'
var minus = '-'
var multiply = '*'
var divide = '/'
var decimal = '.'
function enter(obj, string)
{obj.expr.value += string}
function clear(obj)
{obj.expr.value = ''}
// --End Hiding Here -->
</script>
<form name="calc">
<table border=1>
<td colspan=4><input type="text" name="expr" size=30 action="compute(this.form)"> <tr>
<td><input type="button" value="
7
" onClick="enter(this.form, seven)">
<td><input type="button" value="
8
" onClick="enter(this.form, eight)">
<td><input type="button" value="
9
" onClick="enter(this.form, nine)">
<td><input type="button" value="
/
" onClick="enter(this.form, divide)">
<tr><td><input type="button" value="
4
" onClick="enter(this.form, four)">
<td><input type="button" value="
5
" onClick="enter(this.form, five)">
<td><input type="button" value="
6
" onClick="enter(this.form, six)">
<td><input type="button" value="
*
" onClick="enter(this.form, multiply)">
<tr><td><input type="button" value="
1
" onClick="enter(this.form, one)">
<td><input type="button" value="
2
" onClick="enter(this.form, two)">
<td><input type="button" value="
3
" onClick="enter(this.form, three)">
<td><input type="button" value="
-
" onClick="enter(this.form, minus)">
<tr><td colspan=2><input type="button" value="
0
" onClick="enter(this.form, zero)">
<td><input type="button" value="
.
" onClick="enter(this.form, decimal)">
<td><input type="button" value="
+
" onClick="enter(this.form, plus)">
<tr><td colspan=2><input type="button" value="
=
" onClick="compute(this.form)">
<td colspan=2><input type="button" value="AC" size= 3 onClick="clear(this.form)"> </table>
</form>
</body>
</html>
程序代码：