Question

这就是我输入的内容。对于这种表单方法，我想在答案输入字段中得到答案。 PHP无法正常工作。我无法理解什么是错的

  <form action="index.html" method="get">
       <h1>Calculator</h1>
       <a>Num 1</a>&nbsp;&nbsp; <input type="text" name="num1" value=""><br><br>
       <a>Num 2</a>&nbsp;&nbsp; <input type="text" name="num2" value=""><br><br>
       <a>Answer</a>&nbsp; <input type="text" name="ans" value=""><br><br>
       <button type="button" name="add">+</button>
       &nbsp;&nbsp;&nbsp; <button type="button" name="subtract">-</button>
       &nbsp;&nbsp;&nbsp; <button type="button" name="multiply">*</button>
       &nbsp;&nbsp;&nbsp; <button type="button" name="devide">/</button>
     </form>

<?php
if (isset($_GET["add"]) == 'add') {
  $number1 = $_GET['num1'];
  $number2 = $_GET['num2'];
  $answer = $_GET['ans'];

  $_GET['ans'] = $_GET['num1'] + $_GET['num2'];
  $_GET['ans'];
 }

＆GT;

Answer 1

首先错误的是这一行：

if (isset($_GET["add"]) == 'add') {

isset()会返回true或false，因此虽然您可以将其与add进行比较，但总体上会导致true，但它没有任何意义。

通过为所有按钮指定相同的名称和不同的值，您可以更轻松地实现这一目标：

<button type="submit" name="action" value="add">+</button>
<button type="submit" name="action" value="subtract">-</button>
<button type="submit" name="action" value="multiply">*</button>
<button type="submit" name="action" value="divide">/</button>

请注意，我还将type更改为submit，button类型不会提交您的表单！
另外，将action="index.html"更改为action="index.php"，.html文件根本不会执行任何PHP代码。

现在您可以通过一个简单的开关选择您的操作：

switch ($_GET['action']) {
    case 'add':
        $answer = $_GET['num1'] + $_GET['num2'];
        break;
    case 'subtract':
        // your substract code
        break;
    case 'multiply':
        // your multiply code
        break;
    case 'divide':
        // your divide code
        break;      
}

最后，但并非最不重要的是，在HTML已经打印完毕后计算出来。您不能只回写$_GET并期望已经打印的HTML字段发生变化。因此，将PHP放在前面并将结果输出到输入字段：

<?php
if ( isset($_GET['action']) ) {
    switch ($_GET['action']) {
        case 'add':
            $answer = $_GET['num1'] + $_GET['num2'];
            break;
        case 'subtract':
            // your substract code
            break;
        case 'multiply':
            // your multiply code
            break;
        case 'divide':
            // your divide code
            break;      
    }
}
?>

<form action="index.php" method="get">
    Num 1 <input type="text" name="num1"><br><br>
    Num 2 <input type="text" name="num2"><br><br>
    Answer <input type="text" name="ans" value="<?php echo $answer; ?>"><br><br>

    <button type="submit" name="action" value="add">+</button>
    <button type="submit" name="action" value="subtract">-</button>
    <button type="submit" name="action" value="multiply">*</button>
    <button type="submit" name="action" value="divide">/</button>
</form>

Answer 2

你应该按下你的按钮=＆＃34;提交＆＃34;

Answer 3

检查一下，我没有测试过。

解决方案1 

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
<form method="get" action="#">

Enter the First Number <input type="text" name="number1"> <br><br>

Enter the Second Number <input type="text" name="number2"><br><br>

Choose the operation 

Addition <input type="radio" name="op" value="add" checked>

Subtraction <input type="radio" name="op" value="sub">

Multiplication <input type="radio" name="op" value="mul">

Division<input type="radio" name="op" value="div"><br><br>

 <input type="submit" name="Submit" value="Submit">

</form>
</body>
</html>

<?php

if ( $op == "add" ) {
  echo "$number1 + $number2 = ";
  echo $number1 + $number2;
}

if ( $op == "sub" ) {
  echo "$number1 - $number2 = ";
  echo $number1 - $number2;
}

if ( $op == "mul" ) {
  echo "$number1 * $number2 = ";
  echo $number1 * $number2;
}

if ( $op == "div" ) {
  echo "$number1 / $number2 = ";
  echo $number1 / $number2;
}

?>

解决方案2

<html>
<head>
<title>Simple PHP Calculator</title>
</head>
<body>
    <form method="POST" action="#">
        <input type="text" name="value1">
        <input type="text" name="value2">
        <select name="action">
            <option>+</option>
            <option>-</option>
            <option>*</option>
            <option>/</option>
        </select>
        <input type="submit" name="submit" value="Calculate Now'">
    </form>
</body>
</html>
<?php
if(isset($_POST["submit"]))
{
    $value1 = $_POST["value1"];
    $value2 = $_POST["value2"];
    $action = $_POST["action"];

if($action==”+”)
    {
    echo "<b>Addition : - </b>" . ($value1+$value2) . "\n\n";
    }

if($action==”-“)
    {
    echo "<b>Subtraction : -</b>" . ($value1-$value2). "\n\n";
    }

if($action==”*”)
    {
    echo "<b>Multiplication : -</b>" . ($value1*$value2). "\n\n";
    }

if($action==”/”)
    {
    echo "<b>Division : - </b>" . ($value1)/($value2) . "\n\n";
    }
}
?>

创建一个php计算器

3 个答案: