General Functions
Retries a page from the server using GET method
Retries a page from the server using POST method
Checks if the variable is an integer.
Checks if the variable is an float number.
Checks if the variable is an hexadecimal number.
Checks if the variable is an number compatible with money format.
Checks if the variable is a valid date (mm/dd/yyyy).
Checks if the variable is a valid time (hh:mi).
Checks if the variable looks like an email address.