php之实现九宫格表格和计算器 -

代码块
<?php
/**
 * 使用定界符heredoc实现九宫格
 */
echo <<<EOF
    <table border="1" width="150px" height="150px">
EOF;
for ($i = 0; $i< 9; $i++) {
    if ($i%3==0) {
        $color =  '#'.substr(md5(rand()),0,6);
        echo <<<EOF
        <tr><td bgcolor="$color">$i</td>
EOF;
    } else {
        $color =  '#'.substr(md5(rand()),0,6);
        echo <<<EOF
        <td bgcolor="$color">$i</td>
EOF;
    }
}
echo <<<EOF
    </table>
EOF;
?>
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
             <meta name="viewport"
                   content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
                         <meta http-equiv="X-UA-Compatible" content="ie=edge">
             <title>计算器</title>
</head>
<body>
<form action="" method="post">
<p></p>
    <input type="number" name="num1" id="" width="20px"><br>
    <input type="radio" value="+" name="operator">+<input type="radio" name="operator" value="-">-<input type="radio" name="operator" value="*">*<input type="radio" name="operator" value="/">/&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<button type="submit">=</button>
<br><input type="number" name="num2">
</form>
</body>
</html>
<?php
if (!empty($_POST)) {
   switch ($_POST['operator']) {
       case "+" :
           echo(bcadd($_POST['num1'],$_POST['num2']));
           break;
       case '-' :
           echo(bcsub($_POST['num1'],$_POST['num2']));
           break;
       case '*' :
           echo(bcmul($_POST['num1'],$_POST['num2']));
           break;
       case '/' :
           echo(bcdiv($_POST['num1'],$_POST['num2']));
           break;
   }
}
效果