URL Decoder

URL encoding, also known as "percentage encoding", is a

mechanism for encoding information in a single resource identifier (URI).

Although it is known as URL encoding, it is actually used more generally

within the core Single Resource Identifier (URI), which includes

both a single resource locator (URL) and a single resource name (URN).

Thus, it is also used when preparing data of the type

"application/x-www-form-urlencoded", as it is often used when

presenting HTML form data in HTTP requests.

What is URL decoding and why is it required?

URL decoding is the reverse process of URL encoding.It

is used to analyze query strings or path parameters

passed in the URL.It is also used to decode

HTML form parameters, which are presented in MIME format with

the application/XWW-FORM-URLENCODE

URLs, as you may know, can only contain a limited

set of characters from the US-ASCII character set.These characters include

alphabets (A-z a-z), numbers (0-9), hyphen (-), underscore (_), tilde (~) and

Any character outside this allowed set is encoded

using URL encoding or percentage encoding.

This is why it becomes necessary to decode the query strings

or path parameters passed to the URL in order to get the actual values.

A good example of where this might be needed. Let's

say you need to pass another url as a parameter in the url. You can't substitute this url directly, that's

where url encoding comes to the rescue.

// http%3A%2F%2Fexample.com%2Findex-2.php

$url = urlencode( 'http://example.com/index-2.php' );

// http://example.com/index.php?url=http%3A%2F%2Fexample.com%2Findex-2.php

echo 'http://example.com/index.php?url=' . $url;