Url endings

[ShaolinF]

Hi Guys,

 

I've always wondered how people do this but on the end of URLs of php sites I find these random digits like id=23?e102 etc. How do they do that ? I've never really managed to figure out how to do that.

[trq]

<a href="foo.php?var=12543">link</a>

 

foo.php

<?php

  if (isset($_GET['var'])) {
    echo $_GET['var'];
  }

?>

[cooldude832]

They are called GET variables and are created in a  multiple of ways.  First a form can be processed via get and list all input values in the url in the fashion of key=value&key2=value2.  Secondly they can be created from hyperlinks a big advantage to using them because you can create a link that has 1 page to a dynamic content. (like a photo gallery the id could be which image to display).  The final way is they can mainipulated by the user to make it what they want.  A danger to them for they could get info out of your mysql you don't want so be careful and only use when needed.  Fyi they also help with SEO because many serach engine can follow GET where POST/SESSIONs fail

[teng84]

what are you asking the randomizing or the query string

$id=rand(10,100);

<a href="foo.php?var=".$id>

[ShaolinF]

Thanks Guys. This is cool stuff. Can you guys give me an example of this in action ?

[per1os]

www.google.com

 

Do a search.

[Psycho]

Create two pages as follows (left out the basic HTML):

 

page1.php:

<a href="page2.php?value=A">Value A</a>
<a href="page2.php?value=B">Value B</a>

 

page2.php:

<?php

  if (isset($_GET['value'])) {

    echo "You clicked Value $_GET['value']";

  } else {

    echo "You didn't click one of the links on page1!";

  }

?>

 

 

[ShaolinF]

Oh I see. So basically you can have dozens of links in your html and they all link to an IF statement in php file. Quite straight forward.

 

So what does the isset mean ? All the answers I have come across are too complicated.

[per1os]

www.php.net/isset

 

It checks if a variable has been set or not.

[LiamProductions]

That is easy stuff, Use your best friend Google

[Psycho]

Oh I see. So basically you can have dozens of links in your html and they all link to an IF statement in php file. Quite straight forward.

 

Not sure if you really get it. The links do not link to an if statement. The links simply link to a page AND include variables and their values within that link. The page that is being linked to can access those values using $_GET[variablename]

 

So, when using this link www.mypage.com/index.php?val1=a&val2=b

 

the page index.php would have two variable available to it:

 

$_GET['val1'] would equal 'a'

$_GET['val2 would equal 'b

[ShaolinF]

Oh I see. So basically you can have dozens of links in your html and they all link to an IF statement in php file. Quite straight forward.

 

Not sure if you really get it. The links do not link to an if statement. The links simply link to a page AND include variables and their values within that link. The page that is being linked to can access those values using $_GET[variablename]

 

So, when using this link www.mypage.com/index.php?val1=a&val2=b

 

the page index.php would have two variable available to it:

 

$_GET['val1'] would equal 'a'

$_GET['val2 would equal 'b

Thanks, very informative.

 

What if I had the following links:

 

<a href="page2.php?value=A">Value A</a>

<a href="page2.php?value=B">Value B</a>

 

When I click and it takes me to the IF statement, I want be able to differ between the value contained. For example, if 'value' is 'A' then echo A, whereas if 'value' is 'B' then echo b.

[teng84]

switch($_GET['value'])

{

case 'a':

echo 'this is teng';

break;

case 'b':

echo 'this is teng again';

break;

//optional

default:

echo 'hi im teng';

break;

}

[ShaolinF]

Ah good ol case. Thanks.

 

what if I used the rand function to create random integers. How would I detect it in the php file ?

[pyrodude]

This would be an easy example of a randnum.php file using $_GET and random numbers:

 

<?php
if (isset($_GET[randnum])) {
    $rand2 = rand(0,100);
    $message = "Your random number was $_GET[randnum]<br><br>To get a new one, click <a href=\"randnum.php?randnum=$rand2\">here</a>";
}
else {
    $randnum = rand(0,100);
    $message = "You do not have a random number  =(<br><br>To get a random number, click <a href=\"randnum.php?randnum=$randnum\">here</a>";
}
?>
<html>
<head><title>Random number!</title></head>
<body>
<?=$message?>
</body>
</html>