PHP 檢查 網頁是否有傳值/變數是否有初始化的防呆方法 [php提示Notice： Undefined index解決方法]

資料來源: https://www.cnblogs.com/apolloren/p/8270858.html#:~:text=php%E6%8F%90%E7%A4%BANotice%3A%20Undefined,index%E9%97%AE%E9%A2%98%2CUndefined%20index%3A%E6%98%AF%E6%8C%87%E4%BD%A0%E7%9A%84%E4%BB%A3%E7%A0%81%E9%87%8C%E5%AD%98%E5%9C%A8%EF%BC%9A%E2%80%9C%E5%8F%98%E9%87%8F%E8%BF%98%E6%9C%AA%E5%AE%9A%E4%B9%89%E3%80%81%E8%B5%8B%E5%80%BC%E5%B0%B1%E4%BD%BF%E7%94%A8%E2%80%9D%E7%9A%84%E9%94%99%E8%AF%AF%EF%BC%8C%E8%BF%99%E4%B8%AA%E4%B8%8D%E6%98%AF%E8%87%B4%E5%91%BD%E9%94%99%E8%AF%AF%EF%BC%8C%E4%B8%8D%E4%BC%9A%E8%AE%A9%E4%BD%A0%E7%9A%84php%E4%BB%A3%E7%A0%81%E8%BF%90%E8%A1%8C%E5%BC%BA%E8%A1%8C%E4%B8%AD%E6%AD%A2%EF%BC%8C%E4%BD%86%E6%98%AF%E6%9C%89%E6%BD%9C%E5%9C%A8%E7%9A%84%E5%87%BA%E9%97%AE%E9%A2%98%E7%9A%84%E5%8D%B1%E9%99%A9…

Code

<?php
	if(isset($_GET["page"]))
	{
		$page = $_GET['page'];	
	}
	else
	{
		$page = -1;
	}
?>