Question

我想根据来自database.if的值更改标签选项。＆＃34; 1＆＃34;我想显示不同的选项，并为其他值显示不同的选项。

<<!DOCTYPE html>
    <html>
    <head>
        <title>select</title>
    </head>
    <?php

    if(isset($_POST['submit']))
    {

        $number=$_POST['number'];
        //echo $number;
    if ($number=="1")
    { 

         echo "<select name='subject'>
         <option  value='1'>chemistry</option>
         <option  value='2'>Physics</option>
         <option  value='3'>Biology</option>
         <option  value='4'>Maths</option></select>"
    }
    else
    {
    echo "<select name='subject'>
          <option  value='5'>english</option>
          <option  value='6'>computer</option>
          <option  value='7'>Biology</option>
          <option  value='8'>Maths</option></select>"
    }
    ?>
    <body>
    <form method="post" action="select.php"> 
    <input type="text" name="number" value="">
    <input type="submit" name="submit" value="submit">
    </form>
    </select>
    </body>
    </html>

Answer 1

由于

此处;

<option value='4'>Maths</option></select>"

以及此处<option value='8'>Maths</option></select>"
第一个if()条件缺少结束}。

所以最后的代码是

<!DOCTYPE html>
<html>
<head>
    <title>select</title>
</head>
<?php

    if(isset($_POST['submit']))
    {

        $number = $_POST['number'];
        //echo $number;
        if ( $number == "1" )
        {

            echo "<select name='subject'>
         <option  value='1'>chemistry</option>
         <option  value='2'>Physics</option>
         <option  value='3'>Biology</option>
         <option  value='4'>Maths</option></select>";
        }
        else
        {
            echo "<select name='subject'>
          <option  value='5'>english</option>
          <option  value='6'>computer</option>
          <option  value='7'>Biology</option>
          <option  value='8'>Maths</option></select>";
        }
    }

?>
<body>
<form method="post" action="select.php">
    <input type="text" name="number" value="">
    <input type="submit" name="submit" value="submit">
</form>
</select>
</body>
</html>

Answer 2

你错过了;在两个回声结束时：

if(isset($_POST['submit']))
{

    $number=$_POST['number'];
    //echo $number;
    if ($number=="1")
    { 

         echo "<select name='subject'>
         <option  value='1'>chemistry</option>
         <option  value='2'>Physics</option>
         <option  value='3'>Biology</option>
         <option  value='4'>Maths</option></select>";
    }
    else
    {
          echo "<select name='subject'>
          <option  value='5'>english</option>
          <option  value='6'>computer</option>
          <option  value='7'>Biology</option>
          <option  value='8'>Maths</option></select>";
     }
}
?>

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Answer 3

if(isset($_POST['submit']))
{
    $number=$_POST['number'];
    //echo $number;
    if ($number=="1")
    { 

        echo "<select name='subject'>
        <option  value='1'>chemistry</option>
        <option  value='2'>Physics</option>
        <option  value='3'>Biology</option>
        <option  value='4'>Maths</option></select>"; //missing ; here
    }
    else
    {
        echo "<select name='subject'>
        <option  value='5'>english</option>
        <option  value='6'>computer</option>
        <option  value='7'>Biology</option>
        <option  value='8'>Maths</option></select>";  //missing ; here
    }
}  // missing } here

如何根据来自数据库的值更改选择标记值

3 个答案: