Variables From External SourcesHTML Forms (GET and POST)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:
Example #1 A simple HTML form <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> There are only two ways to access data from HTML forms. Currently available methods are listed below:
Example #2 Accessing data from a simple POST HTML form
Using a GET form is similar except the appropriate
GET predefined variable can be used instead. GET also applies to the
PHP also understands arrays in the context of form variables (see the related faq). For example, related variables may be grouped together, or this feature may be used to retrieve values from a multiple select input. For example, let's post a form to itself and upon submission display the data:
Example #3 More complex form variables
IMAGE SUBMIT variable namesWhen submitting a form, it is possible to use an image instead of the standard submit button with a tag like: <input type="image" src="image.gif" name="sub" /> When the user clicks somewhere on the image, the accompanying form will be transmitted to the server with two additional variables, sub_x and sub_y. 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. HTTP CookiesPHP transparently supports HTTP cookies as defined by » RFC 6265. Cookies are a mechanism for storing data in the remote browser and thus tracking or identifying return users. It is possible to set cookies using the setcookie 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 header function. Cookie data is then available in the appropriate cookie data arrays, such as $_COOKIE as well as in $_REQUEST. See the setcookie manual page for more details and examples.
If multiple values should be assigned to a single cookie variable, they can be assigned as an array. For example:
That will create two separate cookies although MyCookie will now be a single array in the script. If just one cookie should be set with multiple values, consider using serialize or explode on the value first. Note that a cookie will replace a previous cookie by the same name in the browser unless the path or domain is different. So, for a shopping cart application a counter may be kept, and passed along. I.e. Example #4 A setcookie example
Dots in incoming variable namesTypically, 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:
For this reason, it is important to note that PHP will automatically replace any dots in incoming variable names with underscores. Determining variable typesBecause 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: gettype, is_array, is_float, is_int, is_object, and is_string. See also the chapter on Types. HTTP being a text protocol, most, if not all, content that comes in Superglobal arrays, like $_POST and $_GET will remain as strings. PHP will not try to convert values to a specific type. In the example below, $_GET["var1"] will contain the string "null" and $_GET["var2"], the string "123". /index.php?var1=null&var2=123 Changelog
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