GET and POST

**Termana** · 09-10-2009, 08:12 AM

In this tutorial, I will show you a simple example of using POST or GET in a form on a page to simply print “Hello, NAMEHERE”. Of course, POST and GET can be used for better things than this, like sending form information, but this will be enough so that I can show you the difference between them.

So, firstly, we have our form

Code:


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

<head>

  <meta content="text/html; charset=ISO-8859-1"

 http-equiv="content-type">

  <title></title>

</head>

<body>

<form method="post" name="posttest">Name: <input

 name="namevar">

<input name="Submit" value="Submit" type="submit">

</form>

</body>

</html>

Notice in the form tag how we have set method to “post”, this means that the form will submit all values with the post method (so in this case, it will post a variable called namevar). In PHP we can retrieve variables from the post method by using $_POST[‘variablename’]. Since we are using a page that is posting to itself, we will test to see weather the variable exists before we echo anything.

Code:


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

<head>

  <meta content="text/html; charset=ISO-8859-1"

 http-equiv="content-type">

  <title></title>

</head>

<body>

<?php if ($_POST['namevar'] != "")

{

echo 'Hello, ', $_POST['namevar'];

}?>

<form method="post" name="posttest">Name: <input

 name="namevar">

<input name="Submit" value="Submit" type="submit">

</form>

</body>

</html>

Take notice of how when the page refreshes, the URL doesn’t change.

Now we will use the GET method. First we need to change our form to use the GET method:

Code:


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

<head>

  <meta content="text/html; charset=ISO-8859-1"

 http-equiv="content-type">

  <title></title>

</head>

<body>

<form method="get" name="gettest">Name: <input

 name="namevar">

<input name="Submit" value="Submit" type="submit">

</form>

</body>

</html>

In PHP, we can get GET variables by using $_GET[‘variablename’] and again, before printing this variable out, we will test to see if its there.

Code:


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

<head>

  <meta content="text/html; charset=ISO-8859-1"

 http-equiv="content-type">

  <title></title>

</head>

<body>

<?php if ($_GET['namevar'] != "")

{

echo 'Hello, ', $_GET['namevar'];

}?>

<form method="get" name="gettest">Name: <input

 name="namevar">

<input name="Submit" value="Submit" type="submit">

</form>

</body>

</html>

However, notice this time that it when the page refreshes it has appended the variable onto the end of the url in the manner of ?namevar=NAMEHERE

GET variables are restricted in length by URL length restrictions. Generally you would use GET to, you guessed it, GET information. Take a forum for example, most forums will use GET variables to show you a topic. URLs with GET variables can be bookmarked, so this is a good idea. However, when you post a message, it uses post variables. For more information on GET vs POST, you can google it, but be careful, sometimes the explanations you find can be confusing.

If this tutorial has been helpful, don’t forget to +rep me!