A set of PHP pen questions

In PHP, the name of the current script (excluding the path and query string) is recorded in the predefined variable

1. in PHP, the name of the current script (excluding the path and query string) is recorded in the predefined variable
(1), and the URL to the current page is recorded in the predefined variable (2.
2. Execution section Output (3 ).
4. The role of the array function arsort is (6); the role of the statement error_reporting (2047) is (7 ).
5. the format of the database connection string in PEAR is (8 ).
6. write a regular expression and overwrite all JS/VBS scripts on the webpage (that is, remove the script tag and its content): (9 ).
7. install PHP using the Apache module in the http. in the conf file, first use statement (10) to dynamically load the PHP module, and then use statement (11) to make Apache process all files with the extension of php as PHP scripts.
9. attributes of the class can be serialized and saved to the session, so that the entire class can be restored later. the Function used is (14 ).
11. the meaning of left join in SQL is (16 ). If tbl_user records the student's name and student ID, tbl_score records the student's student ID (ID) (which is not recorded after some students take the test) to print the name of each student and the total score of each subject, use the SQL statement (17)