External PHP variables_PHP tutorial

HTML forms (GET and POST)
When a form is submitted to a PHP script, the variables obtained from the form will automatically be made available by the PHP script. Please refer to the following example:

Example 5-2. Simple form variable (simple form variable)

When submitted, PHP will create a variable "$name", which will contain any Enter the content in "Name" in the form.
PHP also knows how to contextualize form variables, but only once. You can, for example, declare a set of variables simultaneously, or use this feature to retrieve values ​​from multiple selection inputs:
　
Example 5-3. More complex form variables

If PHP's track_var feature is turned on, any structure settings or directives about it, then variable submissions via POST or GET mode will find it appropriate to use the global associative arrays "$HTTP_POST_VARS" and "$HTTP_GET_VARS".
Graphic submission variable name
When submitting a form, it is possible to use an image instead of the standard labeled submit button, for example:

When the user clicks the image , the corresponding form will be sent to the server using two additional variables (sub_x and sub_y). They contain information about where the user clicked on the graphic. This will contain the actual variable name sent from the browser (even including underscores), but PHP will automatically convert it to the underlined form.
HTTP Cookies
PHP of course supports HTTP Cookies defined by Netscapes Spec. Cookies are a device that stores data on a remote browser and is used to track and authenticate a user's identity. You can use the SetCookie() function to set cookies. Cookies are part of the HTTP header, so the SetCookie program must be called before being output to the browser. This is similar to the setting of the Header() function. Any cookies sent from the server to the user will automatically be converted into a PHP variable, just like data using GET and POST modes.
If you wish to assign multiple values ​​to a single cookie, simply add a "[ ]" after the cookie name. For example:
SetCookie ("MyCookie[]", "Testing", time()+3600);
Note that if the domain or path on your browser is not the same, the cookie will use the same name to replace a previous cookie. So, for a shopping list application, you might want to keep a counter and pass it through a cookie, for example:

Example 5-4. SetCookie Example (example of setting cookies)
$Count++; >SetCookie ("Count", $Count, time()+3600);
SetCookie ("Cart[$Count]", $item, time()+3600);

Environment variables
PHP automatically uses environment variables as ordinary variables in PHP. Examples are as follows.
echo $HOME; /* Shows the HOME environment variable, if set. */
Since information is passed in with GET, Post, Cookie and other mechanisms, and PHP variables are automatically created, sometimes it is best to be accurate Read a variable from the outside environment to make sure you are using the correct version. The getenv() function does this job. You can also use the putenv() function to set an environment variable.

http://www.bkjia.com/PHPjc/531945.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/531945.htmlTechArticleHTML Form (GET and POST) When the form is submitted to the PHP script, the variables obtained from the form will automatically is set to be available by this PHP script. Please refer to the following example: Example 5-2. Simple...