The difference between isset and empty_PHP tutorial

isset($var); //If it is false, it is not defined. If it is not defined, it is false
$var = '';
isset($var); //If it is true, it is true if it is defined
empty($var) ; //If true, return true if the value is empty
$var = '111';
empty($var); //If false, return false if it is not empty

http://www.bkjia.com/PHPjc/317830.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/317830.htmlTechArticleisset($var);//It is false and is not defined. It is not defined and it is false. $var=''; isset( $var);//For true, it is defined to be true empty($var);//If the true value is empty, it will return true. $var='111'; empty($var);//If it is false, it will not be empty. ..