两种方式：1、使用“setcookie(cookiename,null)”语句将cookie的值设置为空；2、使用“setcookie('cookiename','',time()-3600)”语句将cookie的过期时间设置为过去。
本教程操作环境：windows7系统、php7.1版，dell g3电脑
php删除/清除cookie的两种方法
将cookie的值设置为空,即：setcookie('cookiename', '')或者setcookie(cookiename, null);
将cookie的过期时间设置为过去，即：setcookie('cookiename','',time()-3600); 
方法一：将cookie的值设置为空
<?phpsetcookie ( "cookie_user", "test", time () + 60 * 60 * 24 * 30 );setcookie ( "cookie_pass", md5 ( "test" ), time () + 60 * 60 * 24 * 30 );function logout() { setcookie ( "cookie_user", "", time () + 60 * 60 * 24 * 30 ); setcookie ( "cookie_pass", "", time () + 60 * 60 * 24 * 30 );}/* http://www.manongjc.com/article/1253.html */logout ();echo $_cookie ['cookie_user'] . "<br />";echo "you have successfully logged out.";?>
方法二：将cookie的过期时间设置为过去
<?phpsetcookie ( "cookie_user", "test", time () + 60 * 60 * 24 * 30 );setcookie ( "cookie_pass", md5 ( "test" ), time () + 60 * 60 * 24 * 30 );function logout() { setcookie ( "cookie_user", "test", time () - 100 ); setcookie ( "cookie_pass", md5 ( "test" ), time () - 100 );}logout ();echo $_cookie ['cookie_user'] . "<br />";echo "you have successfully logged out.";?>
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以上就是php删除cookie的两种方式是什么的详细内容。