html>
head>
 
/head>
body>
 
?php
if (!empty($_POST)) {
  $data1 = $_POST["data1"];
  $data2 = $_POST["data2"];
  $fuhao = $_POST["fuhao"];
  $result = "";
 
  echo $data1;
  echo $data2;
  echo $fuhao;
  echo $result;
 
 
  if ($fuhao == '+') {
    $result = $data1 + $data2;
  } else if ($fuhao == '-') {
    $result = $data1 - $data2;
  } else if ($fuhao == '*') {
    $result = $data1 * $data2;
  } else if ($fuhao == '/') {
    $result = $data1 / $data2;
  }
} else {
  $data1 = "";
  $data2 = "";
  $fuhao = "";
  $result = "";
}
 
?>
 
form action="caculator.php" method="post">
  input type="text" name="data1" value="?php echo $data1; ?>"/>
  select name="fuhao">
 
    option value="+"
        ?php if ($fuhao == "+") {
          echo 'selected="selected"';
        } ?>>+
    /option>
    option value="-"
        ?php if ($fuhao == "-") {
          echo 'selected="selected"';
        } ?>>-
    /option>
    option value="*"
        ?php if ($fuhao == "*") {
          echo 'selected="selected"';
        } ?>>*
    /option>
    option value="/"
    ?php if ($fuhao == "/") {
      echo 'selected="selected"';
    } ?>>/
    /option>
 
    /option>
  /select>
  input type="text" name="data2" value="?php echo $data2; ?>"/>
  input type="submit" value="="/>
  input name="result" type="text" value="?php echo $result; ?>"/>
  input type="reset"/>
 
/form>
 
 
/body>
/html>