php怎么打开网页

<?php
$url = "http://example.com";
$content = file_get_contents($url);
echo $content;
?>

<?php
$url = "http://example.com";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$content = curl_exec($ch);
curl_close($ch);
echo $content;
?>

<?php
$url = "http://example.com";
$content = file($url);
foreach ($content as $line) {
    echo $line;
}
?>

<?php
$url = "http://example.com";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); // 跟随重定向
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // 忽略 SSL 证书验证
$content = curl_exec($ch);
curl_close($ch);
echo $content;
?>