选择选项时显示未选择选项的表单错误消息

Posted 2023-03-16

【中文标题】选择选项时显示未选择选项的表单错误消息

【英文标题】：Form showing no option is selected error message when options are selected

【发布时间】：2016-08-17 23:14:01

【问题描述】：

我有以下表格：

<form action="#" method="POST" enctype="multipart/form-data">
    from:
    <select name="age_from" id="age_a" onchange="checkages_a()">
        <option value=""></option>
        <?php
        for($i = 17; $i <= 50; ++$i) 
            echo "\t", '<option value="', $i. '">', $i, '</option>', "\n";
        
        ?>
    </select>
    to:
    <select name="age_to" id="age_b" onchange="checkages_b()">
        <option value=""></option>
        <?php
        for($i = 18; $i <= 50; ++$i) 
            echo "\t", '<option value="', $i, '">', $i, '</option>', "\n";
        
        ?>
    </select>
    <input type="radio" name="gender" value="male">Male</input> <br />
    <input type="radio" name="gender" value="female">Female</input><br />
    <input type="submit" class="btn btn-info" 
        name="submit_form" value="Click to start chat! " />

其工作方式是用户可以从gender 和age 中选择两个选项之一并搜索用户。不需要两个选项都完成搜索。

但是，如果没有选择任何选项，我希望它留在当前页面（`random_chat.php），并回显一条消息。

这是我的方法：

$refined_gender = isset($_POST['gender']) ? escape($_POST['gender']) : '';
$age_from       = isset($_POST['age_from']) ? escape($_POST['age_from']) : '';
$age_to         = isset($_POST['age_to']) ? escape($_POST['age_to']) : '';

if (isset($_POST['submit_form']))

if (empty ($refined_gender) || empty($age_from) || empty ($age_to)) 
    echo "<div class='no_user'><p> Please apply at least one of the filters above. </p> </div>";
 else 
// search user

目前，当我将两个搜索选项都留空时，消息会回显，这很好。但是当我搜索男性用户或年龄不为空时，该消息也会回显，这是不应该发生的。

【问题讨论】：

你明白||和&&的区别吗？

【参考方案1】：

if 条件不能反映您想要这样修复它的内容

 if (empty ($refined_gender) && empty($age_from) && empty ($age_to))  
echo "<div class='no_user'><p> Please apply at least one of the filters above. </p> </div>"; 
 else  // search user 

【讨论】：

?? & ??你可能想再看一遍

感谢 RiggsFolly。已编辑！

对不起，这仍然是错误的，请查看@Anant 答案以获得正确的解决方案

@RiggsFolly，你能解释一下吗？你说的是if条件吗？有错吗？

【参考方案2】：

您需要将|| 更改为&&，（其他一些更改也在注释中说明）：-

<form method="POST" enctype="multipart/form-data"> <!-- remove action ='#' -->
from:
<select name="age_from" id="age_a" onchange="checkages_a()"> 
    <option value=""></option>
    <?php
        for($i = 17; $i <= 50; ++$i) 
            if(isset($_POST['age_from']) && $_POST['age_from'] == $i) // to make selected value to be  selected even after form submit
                echo "\t", '<option value="', $i. '" selected ="selected">', $i, '</option>', "\n";
            else
                echo "\t", '<option value="', $i. '">', $i, '</option>', "\n";
            
        
    ?>
</select>
to: 
<select name="age_to" id="age_b" onchange="checkages_b()"> 
    <option value=""></option>
    <?php
        for($i = 18; $i <= 50; ++$i) 
            if(isset($_POST['age_to']) && $_POST['age_to'] == $i)// to make selected value to be  selected even after form submit
                echo "\t", '<option value="', $i. '" selected ="selected">', $i, '</option>', "\n";
            else
                echo "\t", '<option value="', $i. '">', $i, '</option>', "\n";
            
        
    ?>
</select>
<input type="radio" name="gender" value="male">Male</input> <br />
<input type="radio" name="gender" value="female">Female</input><br />
<input type="submit" class="btn btn-info" name="submit_form" value="Click to start chat! " />
<form>

<?php 

$refined_gender = isset($_POST['gender']) ? $_POST['gender'] : ''; // escape gives me undefined function error at my end so i removed it, but if it is working at your end thhen keep it up as it is.
$age_from       = isset($_POST['age_from']) ? $_POST['age_from'] : '';
$age_to         = isset($_POST['age_to']) ? $_POST['age_to'] : '';

if (empty ($refined_gender) && empty($age_from) && empty ($age_to))  // check always with form posted value not submit button value and also cange || to &&
    echo "<div class='no_user'><p> Please apply at least one of the filters above. </p> </div>";
 else 
// search user

?>