您需要使用类或至少是函数的一些封装，以使其更清晰、更清晰。如 cmets 所述，您使用的是基于帖子的条件，因此可以选择 AFRICA 或 ASIA（或者当有人第一次到达此页面时），因此您不能在下面显示两个迭代，而只允许在顶部除非您设置了默认值，或者您隐藏了未在 POST 中调用的值。
我会先创建一个你的业务逻辑的封装版本（这里是一种模型和控制器，但如果你根本不使用任何封装，那么此时，这个概念没关系）：
/vendor/MyClass/Model.php
<?php
namespace MyClass;
class Model
{
private $request, $con;
/**
* @note Make sure to pass in the $_POST and your database connection.
* They don't have to be typed, but it helps keep things working
* and if you have a good IDE, it makes programming easier
*/
public function __construct(array $request, \PDO $con)
{
$this->request = $request;
$this->con = $con;
}
/**
* @note Here you would try and fetch by the POST country.
* It would be better if the key was called "country" and the
* value would be "asia" or "africa" etc. It makes this
* part easier/cleaner
*/
public function getFromRequest(string $def = null)
{
# Determine what country to fetch
if(isset($this->request['asia']))
$country = 'asia';
elseif(isset($this->request['africa']))
$country = 'africa';
# Stop and return nothing OR you are able to return a default
if(empty($country))
return (!empty($def))? $this->get($def) : false;
# Return a successful selection
return $this->get($country);
}
/**
* @note This is just a general query engine that can be reused
*/
public function get(string $country)
{
# Use the injected db connection to query
$query = $this->con->prepare('SELECT `country` FROM `countries` WHERE `continent` = ?');
# Execute. Presuming all your values use title case, you can
# manipulate the string here to make sure whatever is passed
# in will be correct
$fetch = $query->execute([ ucwords(strtolower($country)) ]);
# Create the loop
while($result = $fetch->fetch(\PDO::FETCH_ASSOC)) {
$row[] = $result;
}
# Return the result
return (!empty($row))? $row : false;
}
}
/thisfile.php
<?php
# Include the model
include_once(__DIR__.'/vendor/MyClass/Model.php');
# Create the instance, make sure to pass the post and your db connection
$MyClass = new \MyClass\Model($_POST, $baseblog);
# Fetch the country array, using "africa" as the default for when a
# $_POST is not set
$selCountry = $MyClass->getFromRequest('africa');
# Even though we are sure there will be returned an array of data, it's best
# to check that it's available first, just in case. This should still be
# error/warning-free if you removed "africa" as the default value.
if($selCountry): ?>
<div class="divpays">
<ul>
<?php foreach($selCountry as $cou): extract($cou); ?>
<li style="text-align: center">
<?php echo $country ?>
</li>
<?php endforeach ?>
</ul>
</div>
<?php endif ?>
我应该注意，我没有对此进行测试，但它应该足以获得概念验证。
编辑：
在重新阅读您的帖子后，您可能还尝试在同一页面上获取多个国家/地区并通过一个按钮一次激活它们，希望您可以保持以前点击的国家/地区处于选中状态。此代码在其当前状态下不会这样做。您需要将其创建为基于 ajax 的解决方案，但您可以在这种情况下保持模型原样：
/ajax/country_select.php
<?php
include_once(realpath(__DIR__.'../').'/vendor/MyClass/Model.php');
$MyClass = new \MyClass\Model($_POST, $baseblog);
# Fetch the country array if set, no default
$selCountry = $MyClass->getFromRequest();
# Stop if no country
if(!$selCountry)
return false ?>
<div class="divpays">
<ul>
<?php foreach($selCountry as $cou): extract($cou); ?>
<li style="text-align: center">
<?php echo $country ?>
</li>
<?php endforeach ?>
</ul>
</div>
我这里要用jquery...
/thisfile.php
<h3>Click a country to get started!</h3>
<button class="country-selector">Africa</button>
<button class="country-selector">Asia</button>
<div id="country-drop"></div>
<script>
$(function(){
// Listen for button click
$('.country-selector').on('click', function(e) {
// Stop the button from doing whatever it would normally do
e.preventDefault();
// This is the default data
var dataSet = {
url: '/ajax/country_select.php',
dataType: 'html',
method: 'post',
success: r => {
// We want to append into the country container
$('#country-drop').append(r);
}
};
// Fetch the value from the button
let sel = $(this).text();
// Remove the button because we don't want people to use it again
$(this).replaceWith('');
// Create our post key, again, this would be much better if
// the key was named "country" and the value was the country
// name
dataSet[sel] = true;
// Do the ajax
$.ajax(dataSet);
});
});
</script>