网页计算器 一个JS计算器

一个挺小的javascript网页计算器，界面美化的我想还是不错的，毕竟在没有使用任何图片修饰的情况下，很好看，而且功能挺实用，可以完成基本的数学算数运算，点击“运行代码”可以运行一下看效果。

<meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>计算器</title> <style> button {width:40; border: 1 solid #808080;background-color: #ffffff} </style> <form name="calc"> <table border="4" bordercolorlight="#808080" bordercolor="#808080" width="250" height="38"> <tr><td width="291" height="39" bgcolor="#c0c0c0"> &nbsp; <input type="text" name="input" readonly size="21" style="background-color: #f5f5f5; font-family: arial; border: 1 solid #000000">&nbsp <button name="back" onclick="backspace()">←</button> </td></tr> <tr><td width="291" height="38"> <table border="0" width="100%" height="105" cellpadding="0"> <tr> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="1" onclick="addoperator()">1</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="2" onclick="addoperator()">2</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="3" onclick="addoperator()">3</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="+" onclick="addoperator()">+</button> </td> </tr> <tr> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="4" onclick="addoperator()">4</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="5" onclick="addoperator()">5</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="6" onclick="addoperator()">6</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="-" onclick="addoperator()">-</button> </td> </tr> <tr> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="7" onclick="addoperator()">7</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="8" onclick="addoperator()">8</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="9" onclick="addoperator()">9</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="*" onclick="addoperator()">×</button> </td> </tr> <tr> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="clear" onclick="clearinput()">c</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="0" onclick="addoperator()">0</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="=" onclick="result()">=</button> </td> <td width="25%" height="31" align="center" bgcolor="#c0c0c0"> <button name="/" onclick="addoperator()">÷</button> </td> </tr> </table> </td></tr> </table> </form>
[ctrl+a 全选 注:引入外部js需再刷新一下页面才能执行]