php check if string is empty

1if(empty($var1)){
2    echo 'This line is printed, because the $var1 is empty.';
3}

1if (empty($var)) {
2    echo '$var is either 0, empty, or not set at all';
3}

1function strictEmpty($var) {
2
3    // Delete this line if you want space(s) to count as not empty
4    $var = trim($var);
5    
6    if(isset($var) === true && $var === '') {
7    
8        // It's empty
9    
10    }
11    else {
12    
13        // It's not empty
14    
15    }
16
17}

1empty var php