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</div><hr /><div id="language.variables.external" class="sect1">
<h2 class="title">Variables From External Sources</h2>
<div class="sect2" id="language.variables.external.form">
<h3 class="title">HTML Forms (GET and POST)</h3>
<p class="simpara">
When a form is submitted to a PHP script, the information from
that form is automatically made available to the script. There
are few ways to access this information, for example:
</p>
<p class="para">
<div class="example" id="example-86">
<p><strong>Example #1 A simple HTML form</strong></p>
<div class="example-contents">
<div class="htmlcode"><pre class="htmlcode"><form action="foo.php" method="post">
Name: <input type="text" name="username" /><br />
Email: <input type="text" name="email" /><br />
<input type="submit" name="submit" value="Submit me!" />
</form></pre>
</div>
</div>
</div>
</p>
<p class="para">
As of PHP 5.4.0, there are only two ways to access data from your HTML forms.
Currently available methods are listed below:
</p>
<p class="para">
<div class="example" id="example-87">
<p><strong>Example #2 Accessing data from a simple POST HTML form</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">$_POST</span><span style="color: #007700">[</span><span style="color: #DD0000">'username'</span><span style="color: #007700">];<br />echo </span><span style="color: #0000BB">$_REQUEST</span><span style="color: #007700">[</span><span style="color: #DD0000">'username'</span><span style="color: #007700">];<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
There were some other ways of accessing user input in old PHP versions. These
are listed below. See changelog at the bottom of the page for more details.
<div class="example" id="example-88">
<p><strong>Example #3 Old methods of accessing user input</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// WATCH OUT: these methods ARE NOT supported anymore.<br />// Valid ones were described above.<br /><br />// Using import_request_variables() - this function has been removed in PHP 5.4.0<br /> </span><span style="color: #0000BB">import_request_variables</span><span style="color: #007700">(</span><span style="color: #DD0000">'p'</span><span style="color: #007700">, </span><span style="color: #DD0000">'p_'</span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$p_username</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// These long predefined variables were removed in PHP 5.4.0<br /> </span><span style="color: #007700">echo </span><span style="color: #0000BB">$HTTP_POST_VARS</span><span style="color: #007700">[</span><span style="color: #DD0000">'username'</span><span style="color: #007700">];<br /><br /></span><span style="color: #FF8000">// Using register_globals. This feature was removed in PHP 5.4.0<br /> </span><span style="color: #007700">echo </span><span style="color: #0000BB">$username</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
Using a GET form is similar except you'll use the appropriate
GET predefined variable instead. GET also applies to the
<em>QUERY_STRING</em> (the information after the '?' in a URL). So,
for example, <em>http://www.example.com/test.php?id=3</em>
contains GET data which is accessible with <var class="varname"><var class="varname"><a href="reserved.variables.get.html" class="classname">$_GET['id']</a></var></var>.
See also <var class="varname"><var class="varname"><a href="reserved.variables.request.html" class="classname">$_REQUEST</a></var></var>.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Dots and spaces in variable names are converted to underscores. For
example <em><input name="a.b" /></em> becomes
<em>$_REQUEST["a_b"]</em>.
</p>
</p></blockquote>
<p class="simpara">
PHP also understands arrays in the context of form variables
(see the <a href="faq.html.html" class="link">related faq</a>). You may,
for example, group related variables together, or use this
feature to retrieve values from a multiple select input. For
example, let's post a form to itself and upon submission display
the data:
</p>
<p class="para">
<div class="example" id="example-89">
<p><strong>Example #4 More complex form variables</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">$_POST</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">'<pre>'</span><span style="color: #007700">;<br /> echo </span><span style="color: #0000BB">htmlspecialchars</span><span style="color: #007700">(</span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$_POST</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">));<br /> echo </span><span style="color: #DD0000">'</pre>'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?><br /></span><form action="" method="post"><br /> Name: <input type="text" name="personal[name]" /><br /><br /> Email: <input type="text" name="personal[email]" /><br /><br /> Beer: <br /><br /> <select multiple name="beer[]"><br /> <option value="warthog">Warthog</option><br /> <option value="guinness">Guinness</option><br /> <option value="stuttgarter">Stuttgarter Schwabenbräu</option><br /> </select><br /><br /> <input type="submit" value="submit me!" /><br /></form></span>
</code></div>
</div>
</div>
</p>
<div class="sect3" id="language.variables.external.form.submit">
<h4 class="title">IMAGE SUBMIT variable names</h4>
<p class="simpara">
When submitting a form, it is possible to use an image instead
of the standard submit button with a tag like:
</p>
<div class="informalexample">
<div class="example-contents">
<div class="htmlcode"><pre class="htmlcode"><input type="image" src="image.gif" name="sub" /></pre>
</div>
</div>
</div>
<p class="simpara">
When the user clicks somewhere on the image, the accompanying
form will be transmitted to the server with two additional
variables, <var class="varname"><var class="varname">sub_x</var></var> and <var class="varname"><var class="varname">sub_y</var></var>.
These contain the coordinates of the
user click within the image. The experienced may note that the
actual variable names sent by the browser contains a period
rather than an underscore, but PHP converts the period to an
underscore automatically.
</p>
</div>
</div>
<div class="sect2" id="language.variables.external.cookies">
<h3 class="title">HTTP Cookies</h3>
<p class="simpara">
PHP transparently supports HTTP cookies as defined by <a href="http://www.faqs.org/rfcs/rfc6265" class="link external">» RFC 6265</a>. Cookies are a
mechanism for storing data in the remote browser and thus
tracking or identifying return users. You can set cookies using
the <span class="function"><a href="function.setcookie.html" class="function">setcookie()</a></span> function. Cookies are part of
the HTTP header, so the SetCookie function must be called before
any output is sent to the browser. This is the same restriction
as for the <span class="function"><a href="function.header.html" class="function">header()</a></span> function. Cookie data
is then available in the appropriate cookie data arrays, such
as <var class="varname"><var class="varname"><a href="reserved.variables.cookies.html" class="classname">$_COOKIE</a></var></var> as well as in <var class="varname"><var class="varname"><a href="reserved.variables.request.html" class="classname">$_REQUEST</a></var></var>.
See the <span class="function"><a href="function.setcookie.html" class="function">setcookie()</a></span> manual page for more details and
examples.
</p>
<p class="simpara">
If you wish to assign multiple values to a single cookie variable, you
may assign it as an array. For example:
</p>
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /> setcookie</span><span style="color: #007700">(</span><span style="color: #DD0000">"MyCookie[foo]"</span><span style="color: #007700">, </span><span style="color: #DD0000">'Testing 1'</span><span style="color: #007700">, </span><span style="color: #0000BB">time</span><span style="color: #007700">()+</span><span style="color: #0000BB">3600</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">setcookie</span><span style="color: #007700">(</span><span style="color: #DD0000">"MyCookie[bar]"</span><span style="color: #007700">, </span><span style="color: #DD0000">'Testing 2'</span><span style="color: #007700">, </span><span style="color: #0000BB">time</span><span style="color: #007700">()+</span><span style="color: #0000BB">3600</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<p class="simpara">
That will create two separate cookies although <var class="varname"><var class="varname">MyCookie</var></var> will now
be a single array in your script. If you want to set just one cookie
with multiple values, consider using <span class="function"><a href="function.serialize.html" class="function">serialize()</a></span> or
<span class="function"><a href="function.explode.html" class="function">explode()</a></span> on the value first.
</p>
<p class="simpara">
Note that a cookie will replace a previous cookie by the same
name in your browser unless the path or domain is different. So,
for a shopping cart application you may want to keep a counter
and pass this along. i.e.
</p>
<div class="example" id="example-90">
<p><strong>Example #5 A <span class="function"><a href="function.setcookie.html" class="function">setcookie()</a></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">if (isset(</span><span style="color: #0000BB">$_COOKIE</span><span style="color: #007700">[</span><span style="color: #DD0000">'count'</span><span style="color: #007700">])) {<br /> </span><span style="color: #0000BB">$count </span><span style="color: #007700">= </span><span style="color: #0000BB">$_COOKIE</span><span style="color: #007700">[</span><span style="color: #DD0000">'count'</span><span style="color: #007700">] + </span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />} else {<br /> </span><span style="color: #0000BB">$count </span><span style="color: #007700">= </span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">setcookie</span><span style="color: #007700">(</span><span style="color: #DD0000">'count'</span><span style="color: #007700">, </span><span style="color: #0000BB">$count</span><span style="color: #007700">, </span><span style="color: #0000BB">time</span><span style="color: #007700">()+</span><span style="color: #0000BB">3600</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">setcookie</span><span style="color: #007700">(</span><span style="color: #DD0000">"Cart[</span><span style="color: #0000BB">$count</span><span style="color: #DD0000">]"</span><span style="color: #007700">, </span><span style="color: #0000BB">$item</span><span style="color: #007700">, </span><span style="color: #0000BB">time</span><span style="color: #007700">()+</span><span style="color: #0000BB">3600</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</div>
<div class="sect2" id="language.variables.external.dot-in-names">
<h3 class="title">Dots in incoming variable names</h3>
<p class="para">
Typically, PHP does not alter the names of variables when they
are passed into a script. However, it should be noted that the
dot (period, full stop) is not a valid character in a PHP
variable name. For the reason, look at it:
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$varname</span><span style="color: #007700">.</span><span style="color: #0000BB">ext</span><span style="color: #007700">; </span><span style="color: #FF8000">/* invalid variable name */<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
Now, what the parser sees is a variable named
<var class="varname"><var class="varname">$varname</var></var>, followed by the string concatenation
operator, followed by the barestring (i.e. unquoted string which
doesn't match any known key or reserved words) 'ext'. Obviously,
this doesn't have the intended result.
</p>
<p class="para">
For this reason, it is important to note that PHP will
automatically replace any dots in incoming variable names with
underscores.
</p>
</div>
<div class="sect2" id="language.variables.determining-type-of">
<h3 class="title">Determining variable types</h3>
<p class="para">
Because PHP determines the types of variables and converts them
(generally) as needed, it is not always obvious what type a given
variable is at any one time. PHP includes several functions
which find out what type a variable is, such as:
<span class="function"><a href="function.gettype.html" class="function">gettype()</a></span>, <span class="function"><a href="function.is-array.html" class="function">is_array()</a></span>,
<span class="function"><a href="function.is-float.html" class="function">is_float()</a></span>, <span class="function"><a href="function.is-int.html" class="function">is_int()</a></span>,
<span class="function"><a href="function.is-object.html" class="function">is_object()</a></span>, and
<span class="function"><a href="function.is-string.html" class="function">is_string()</a></span>. See also the chapter on
<a href="language.types.html" class="link">Types</a>.
</p>
<p class="para">
HTTP being a text protocol, most, if not all, content that comes in
<a href="language.variables.superglobals.html" class="link">Superglobal arrays</a>,
like <var class="varname"><var class="varname"><a href="reserved.variables.post.html" class="classname">$_POST</a></var></var> and <var class="varname"><var class="varname"><a href="reserved.variables.get.html" class="classname">$_GET</a></var></var> will remain
as strings. PHP will not try to convert values to a specific type.
In the example below, <var class="varname"><var class="varname"><a href="reserved.variables.get.html" class="classname">$_GET["var1"]</a></var></var> will contain the
string "null" and <var class="varname"><var class="varname"><a href="reserved.variables.get.html" class="classname">$_GET["var2"]</a></var></var>, the string "123".
<div class="example-contents">
<div class="cdata"><pre>
/index.php?var1=null&var2=123
</pre></div>
</div>
</p>
</div>
<div class="sect2" id="language.variables.external.changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.4.0</td>
<td>
<a href="security.globals.html" class="link">Register Globals</a>,
<a href="security.magicquotes.html" class="link">Magic Quotes</a> and
<a href="ini.core.html#ini.register-long-arrays" class="link">register_long_arrays</a>
has been removed
</td>
</tr>
<tr>
<td>5.3.0</td>
<td>
<a href="security.globals.html" class="link">Register Globals</a>,
<a href="security.magicquotes.html" class="link">Magic Quotes</a> and
<a href="ini.core.html#ini.register-long-arrays" class="link">register_long_arrays</a>
became deprecated
</td>
</tr>
<tr>
<td>4.2.0</td>
<td>
<a href="ini.core.html#ini.register-globals" class="link">register_globals</a>
directive defaults to <em class="emphasis">off</em>.
</td>
</tr>
<tr>
<td>4.1.0</td>
<td>
<a href="language.variables.superglobals.html" class="link">Superglobal arrays</a>,
like <var class="varname"><var class="varname"><a href="reserved.variables.post.html" class="classname">$_POST</a></var></var> and <var class="varname"><var class="varname"><a href="reserved.variables.get.html" class="classname">$_GET</a></var></var> became
available
</td>
</tr>
</tbody>
</table>
</p>
</div>
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