Required fieldsSome of your fields will be required. In other words, visitors have to enter something in the field. The following script checks that a first name was entered:
if (ereg(".", $first_name) == 1)
echo "First name: ", "$first_name";
$verify = "OK";
print ("<b>Error:</b> A first name is required.");
$verify = "bad";
ereg means "evaluate regular
expression". "Regular expressions" are the UNIX function for finding patterns in strings of letters and numbers.
ereg is followed by parentheses, and you can put three arguments in the parentheses. The arguments are separated by commas. The first argument is the pattern to search for, usually surrounded by quotation marks. The second argument is where
ereg is to search, usually a variable. The third, optional, argument is an array to put matches into. This argument is a variable.
ereg returns either a "0" (false) or a "1" (true).
. or period is a regular expression wild card meaning "any character."
(ereg(".", $first_name) == 1) means "the variable '$first_name' contains anything". If this expression is true, then the first name is printed, and the variable
$verify is set to "OK".
else argument executes when
ereg returns "0" (false).
There are three other versions of the
Alternative means to the same end
ereg_replace uses three arguments: the first is the pattern to search for, the second is the pattern to replace the first pattern, and the third is where to search (a variable).
eregi is the same as
ereg, except that it's not case-sensitive (i.e., it doesn't differentiate upper- and lower-case letters).
eregi_replace is not case sensitive
if (ereg(".", $first_name) == 1) can be simplified to
if ($first_name). I used the longer form to show how to use
ereg in a simple example.
Checking e-mail addressesThe following
ereg arguments test validity of e-mail addresses: