Question

我在PHP中验证表单选择列表（下拉列表）时遇到了一个奇怪的问题。在我的HTML中，当我使用0（零）作为<option>值并在PHP中，检查传入值是否等于0然后不提交表单，那么表单即使我也没有提交选择其他<option>值，例如“德里”而不是0.这是我的HTML和PHP代码，可以更好地解释你：

HTML

<form name="form1" method="get" action="">
    <table width="50%" border="0" align="center">
        <tr>
            <th><label for="selcity">City:</label></th>
            <td><select name="selcity" id="selcity">
            <option value="0">Select Your City</option>
            <option value="Chandigarh" <?php if($city == "Chandigarh") echo "selected='selected'"; ?> >Chandigarh</option>
            <option value="Delhi" <?php if($city == "Delhi") echo "selected='selected'"; ?> >Delhi</option>
            <option value="Shimla" <?php if($city == "Shimla") echo "selected='selected'"; ?> >Shimla</option>
            </select></td>
        </tr>
        <tr>
            <td>&nbsp;</td>
            <td><input type="submit" name="btnsubmit" value="Submit" /></td>
        </tr>
    </table>
</form>

PHP

<?php
// Default form values
$city = NULL;

if(isset($_GET['btnsubmit']))
{
    $city = $_GET['selcity'];

    $errors = array();
    if($city == 0)
    {
        $errors[] = "Please select your city.";
    }

    if(count($errors) == 0)
    {
        // Do some mysql queries for saving data in table
        echo "You are registered.";
    }
    else
    {
        $error_list = "<div id='error'><strong>There are following errors with this form:</strong><ul>";
        foreach($errors as $error)
        {
            $error_list .= "<li>" . $error . "</li>";
        }
        $error_list .= "</ul></div>";
        echo $error_list;
    }
}
?>

但是，当我将HTML代码更改为

时

<option value="">Select Your City</option>

和PHP代码

if($city == "")
{
    $errors[] = "Please select your city.";
}

然后问题就解决了。为什么呢？

PHP表单选择列表验证奇怪的问题

0 个答案: