如果我符合php中的條件，如何在同一頁面上顯示結果？

Question

如果選擇了第二個選項，我想在同一頁面上顯示一個復選框，請您幫我提供代碼。

這是我當前的代碼：

<form action="form1.php" method="post">
<?php

$company = array (1 => 'One', 'Two', 'Three');
echo '<fieldset>
<select name="companys">';
foreach ($company as $key => $value) {
    echo "<option value=\"$key\">$value</option>\n";
}
echo '</select>';
if ($company == 2) {
    echo'<p><input type="checkbox" name="tandc" value="terms" />I accept the terms and conditions
    </p>';
} else {
    echo 'OK';
};
echo '</fieldset>';
?>
</form>

Answer 1

假設您將表單發布到某個地方，當前頁面是form1.php。

<form action="form1.php" method="post">
<?php

$company = array(1 => 'One', 2 => 'Two', 3 => 'Three');
echo '<fieldset>
    <select name="companys">';

        foreach ($company as $key => $value) {
            echo "<option value=\"$key\">$value</option>\n";
        }

echo '</select>';

if (isset($_POST['companys']) && $_POST['companys'] == 2) {
    echo'<p><input type="checkbox" name="tandc" value="terms" />I accept the terms and conditions</p>';
} else {
    echo 'OK';
}

echo '</fieldset>';

?>
</form>

Answer 2

***if ($company == 2) {***

$ company被定義為數組，但是您已經提到了字符串。 請檢查。

Answer 3

嘗試這個：

<form action="#" method="post">
<?php

$company = array (1 => 'One', 'Two', 'Three');
echo '<fieldset>
<select name="companys">';
foreach ($company as $key => $value) {
    echo "<option value=\"$key\" onclick='this.form.submit()'>$value</option>\n";
}
echo '</select>';
if ($_POST['companys'] == 2) {
    echo'<p><input type="checkbox" name="tandc" value="terms" onclick="this.form.submit()"/>I accept the terms and conditions
 </p>';
} else {
    echo 'OK';
};
echo '</fieldset>';
?>
</form>

Answer 4

如果下拉值匹配條件，則無需提交表單即可顯示元素，只需使用javascript函數即可，請參見下面的示例代碼

<form action="form1.php" method="post">
    <?php

    $company = array(1 => 'One', 2 => 'Two', 3 => 'Three');
    echo '<fieldset>
        <select name="companys" onchange="check_option(this.value);">';

            foreach ($company as $key => $value) {
                echo "<option value=\"$key\">$value</option>\n";
            }

    echo '</select>';


    echo'<p><input type="checkbox" id="terms" name="tandc" value="terms"  style="display:none;"/>I accept the terms and conditions</p>';


    echo '</fieldset>';

    ?>
    </form>
    <script>
        function check_option(val)
        {
            if(val=='Two')
            {
                document.getElementById('terms').style.display='block';
            }
        }
    </script>