php如何实现单选
实现单选按钮
在HTML表单中创建单选按钮使用<input type="radio">标签,通过name属性将多个单选按钮分组,确保同一时间只能选择其中一个选项。
<form action="process.php" method="post">
<input type="radio" name="gender" value="male"> Male
<input type="radio" name="gender" value="female"> Female
<input type="radio" name="gender" value="other"> Other
<input type="submit" value="Submit">
</form>
处理表单提交
在PHP中通过$_POST或$_GET超全局变量获取用户选择的单选按钮值。使用isset()函数检查是否选择了某个选项。

if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (isset($_POST['gender'])) {
$selectedGender = $_POST['gender'];
echo "Selected gender: " . htmlspecialchars($selectedGender);
} else {
echo "No gender selected.";
}
}
动态生成单选按钮
从数据库或数组中动态生成单选按钮,使用循环遍历选项。
$options = ["male" => "Male", "female" => "Female", "other" => "Other"];
foreach ($options as $value => $label) {
echo "<input type='radio' name='gender' value='$value'> $label";
}
验证单选按钮输入
确保用户提交的数据符合预期,进行基本的验证。

$validOptions = ["male", "female", "other"];
if (isset($_POST['gender']) && in_array($_POST['gender'], $validOptions)) {
$selectedGender = $_POST['gender'];
} else {
echo "Invalid selection.";
}
默认选中选项
通过checked属性设置默认选中的单选按钮。
<input type="radio" name="gender" value="male" checked> Male
使用PHP保持选中状态
在表单提交后,保持用户之前选择的选项。
$selected = $_POST['gender'] ?? '';
foreach ($options as $value => $label) {
$checked = ($value == $selected) ? 'checked' : '';
echo "<input type='radio' name='gender' value='$value' $checked> $label";
}