php man page for urlencode

URLENCODE(3)								 1							      URLENCODE(3)

urlencode - URL-encodes string

SYNOPSIS
       string urlencode (string  $str)

DESCRIPTION
	This  function is convenient when encoding a string to be used in a query part of a URL, as a convenient way to pass variables to the next
       page.

PARAMETERS
	      o $str
		- The string to be encoded.

RETURN VALUES
	Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent ( %) sign followed by two hex  dig-
       its and spaces encoded as plus ( +) signs. It is encoded the same way that the posted data from a WWW form is encoded, that is the same way
       as in application/x-www-form-urlencoded media type. This differs from the RFC 3986 encoding (see rawurlencode(3)) in  that  for	historical
       reasons, spaces are encoded as plus (+) signs.

EXAMPLES
       Example #1

	      urlencode(3) example

	      <?php
	      echo '<a href="mycgi?foo=', urlencode($userinput), '">';
	      ?>

       Example #2

	      urlencode(3) and htmlentities(3) example

	      <?php
	      $query_string = 'foo=' . urlencode($foo) . '&bar=' . urlencode($bar);
	      echo '<a href="mycgi?' . htmlentities($query_string) . '">';
	      ?>

NOTES
       Note

	       Be  careful  about  variables  that  may  match HTML entities. Things like &amp, &copy and &pound are parsed by the browser and the
	      actual entity is used instead of the desired variable name. This is an obvious hassle that the W3C has been telling people about for
	      years. The reference is here: http://www.w3.org/TR/html4/appendix/notes.html#h-B.2.2.

	       PHP  supports  changing	the  argument separator to the W3C-suggested semi-colon through the arg_separator .ini directive. Unfortu-
	      nately most user agents do not send form data in this semi-colon separated format. A more portable way around this is to	use  &amp;
	      instead  of  &  as  the separator. You don't need to change PHP's arg_separator for this. Leave it as &, but simply encode your URLs
	      using htmlentities(3) or htmlspecialchars(3).

SEE ALSO
       urldecode(3), htmlentities(3), rawurlencode(3), rawurldecode(3), RFC 3986.

PHP Documentation Group 													      URLENCODE(3)