PHP variables

- Variable scope: Any variable used inside a function is by default limited to the local function scope.

PHP functions

- Function file: Read a file and create a array separate by new line. - Function file_get_contents: Reads an entire file, starting at the specified offset up to maxlen bytes, into a string. - Function file_put_contents: Append an PHP_EOL to the end of the line and write data to a file. - Funtction time: Store the current Unix timestamp measured in the number of seconds. - Funtction date: Prints the date, formatting a previously stored integer timestamp.

HTML tags

- Html link tag: Used to link the current document to an external resource. - target html tag Set target='_blank' in header, when parse a URL and the return of its components matches a domain name to an external website.

HTML attributes

- Handling text direction with dir attribute: To display languages that uses RTL script