<!--设置表格内居中对齐，表格边框2px-->
<table align="center" border="2px"><tr><td><input type="text" name="number1" size=4></td><td><select name="caculate" size="1"><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option><option value="%">%</option></select></td><td><input type="text" name="number2" size=4></td><td><input type="submit" name="ok" value="计算" size=4></td> </tr>
设置第一行（输入行）
<tr align="center" >
<!--colspan用来合并单元格，使输出数据居中，更美观。--><td width="full" colspan="4"><?phpfunction caculate($numb1,$numb2,$method){switch($method){case ‘+‘:return $numb1+$numb2;break;case ‘-‘:return $numb1-$numb2;break;case ‘*‘:return $numb1*$numb2;break;case ‘/‘:return $numb1/$numb2;break;case ‘%‘:return $numb1%$numb2;break;default:break;}}if(isset($_POST[‘ok‘])){$numb1=$_POST[‘number1‘];$numb2=$_POST[‘number2‘];$method=$_POST[‘caculate‘];if(is_numeric($numb1)&&is_numeric($numb2)){if($method==‘/‘&&$numb2==0){echo "<script>alert(‘除数不能为“0”，请重新输入！‘)</script>";return;}$res=caculate($numb1,$numb2,$method);echo "$numb1 $method $numb2 = $res ";}else{echo "<script>alert(‘您输入的不是数字，请重新输入！‘)</script>";}}?></td></tr>
设置第二行（输出行）
1 <!doctype html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title>网页计算机</title> 6 </head> 7 <style type= "text/css"> 8 ????h1{ 9 ????????font-size=24px;10 ????????text-align: center;11 ????????font-family: "黑体" ;12 ????}13 ????14 ????15 </style>16 <body>17 ????<h1>网页计算器</h1>18 ????<form method="post">19 ????????<table align="center" border="2px">20 ????????<tr>21 ????????????<td>22 ????????????????<input type="text" name="number1" size=4>23 ????????????</td>24 ????????????<td>25 ????????????????<select name="caculate" size="1">26 ????????????????????<option value="+">+</option>27 ????????????????????<option value="-">-</option>28 ????????????????????<option value="*">*</option>29 ????????????????????<option value="/">/</option>30 ????????????????????<option value="%">%</option>31 ????????????????</select>32 ????????????</td>33 ????????????<td>34 ????????????????<input type="text" name="number2" size=4>35 ????????????</td>36 ????????????<td>37 ????????????????<input type="submit" name="ok" value="计算" size=4>38 ????????????</td> 39 ????????</tr>40 ????????<tr align="center" >41 ????????????<td width="full" colspan="4">42 ????????????????<?php43 ????????????????????function caculate($numb1,$numb2,$method)44 ????????????????????{45 ????????????????????????switch($method)46 ????????????????????????{47 ????????????????????????????case ‘+‘:48 ????????????????????????????????return $numb1+$numb2;49 ????????????????????????????????break;50 ????????????????????????????case ‘-‘:51 ????????????????????????????????return $numb1-$numb2;52 ????????????????????????????????break;53 ????????????????????????????case ‘*‘:54 ????????????????????????????????return $numb1*$numb2;55 ????????????????????????????????break;56 ????????????????????????????case ‘/‘:57 ????????????????????????????????return $numb1/$numb2;58 ????????????????????????????????break;59 ????????????????????????????case ‘%‘:60 ????????????????????????????????return $numb1%$numb2;61 ????????????????????????????????break;62 ????????????????????????????default:63 ????????????????????????????????break;64 ????????????????????????}65 ????????????????????}66 ????????????????????if(isset($_POST[‘ok‘]))67 ????????????????????{68 ????????????????????????$numb1=$_POST[‘number1‘];69 ????????????????????????$numb2=$_POST[‘number2‘];70 ????????????????????????$method=$_POST[‘caculate‘];71 ????????????????????????if(is_numeric($numb1)&&is_numeric($numb2))72 ????????????????????????{73 ????????????????????????????if($method==‘/‘&&$numb2==0)74 ????????????????????????????{75 ????????????????????????????????echo "<script>alert(‘除数不能为“0”，请重新输入！‘)</script>";76 ????????????????????????????????return;77 ????????????????????????????}78 ????????????????????????????$res=caculate($numb1,$numb2,$method);79 ????????????????????????????echo "$numb1 $method $numb2 = $res ";80 ????????????????????????}81 ????????????????????????else82 ????????????????????????{83 ????????????????????????????echo "<script>alert(‘您输入的不是数字，请重新输入！‘)</script>";84 ????????????????????????}85 ????????????????????}86 ?????????????????>87 ????????????</td>88 ????????</tr>89 ????</table>90 ????</form>91 ????92 </body>93 </html>完全代码
php+html实现网页计算器
原文地址：http://www.cnblogs.com/ouyangchun/p/7668245.html