PHP-Submit a form to different pages according to variable values

Question

I was wondering in php web page, like

<form method = "post" action = ?>
   Age: <input type = "text" name="age">
   Submit: <input type="submit">
</form>

for example, if the input age larger than 18, then go to page: a.php; else goto b.php

How can we fulfil that, in this current page or do it in the next forwarding page?

More specifically,

if we want to do it in current page,

what I think is action="function()", and inside the function, we do the judgement to go to a.php or b.php. But what is the correct way to write the action and function()? And I saw using onclick="..." as well, what is the difference?

if we want to do it in the next page,

we can write action="c.php" and do the judgement in the c.php page. If so, how to do that in the c.php page?

btw, which way is a common used way?

Thanks, Eve

whats the problem of going to the same page, and handling it according to the age value? — Aris
– Aris, Commented Aug 7, 2013 at 14:18
the second one would be recommended you check for the condition on the second page and then do what ever action you require — user2541120
– user2541120, Commented Aug 7, 2013 at 14:20

Aris · Accepted Answer · 2013-08-07 14:21:31Z

1

Best way to always submit to the same page.

<form method = "post" action = 'c.php'>
   Age: <input type = "text" name="age">
   Submit: <input type="submit">
</form>

in c.php

$age = $_POST['age'];    
if ($age > 18) 
{
   //do something
} else {
    //do something else
}

answered Aug 7, 2013 at 14:21

Aris

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Comments

Daniel W. · Accepted Answer · 2013-08-07 14:22:02Z

1

you could change the action attribut with jQuery like:

$( formSelector ).onsubmit(function() {
    if (parseInt($( inputSelector )).val() > 18) {
        $( formSelector ).attr('action', 'over18.php');
     } else {
        $( formSelector ).attr('action', 'under18.php');
     }
}

but it would be better to make it like this:

form action="switchValue.php"

in that file..

if ((int)$_POST['age'] > 18) {
    include("over18.php");
} else {
    include("under18.php");
}

answered Aug 7, 2013 at 14:22

Daniel W.

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Comments

user2541120 · Accepted Answer · 2013-08-07 14:24:22Z

1

This should be what you are looking for.

Page b.php
<?
if ($_GET['age'] > 18) 
{
    //do some thing
} else {
   //do some thing
}
?>

<form action="b.php">
   Age: <input type = "text" name="age">
   Submit: <input type="submit">
</form>

answered Aug 7, 2013 at 14:24

user2541120

1 Comment

user2541120 Over a year ago

Did the answer help you?

Your Common Sense · Accepted Answer · 2013-08-07 14:19:42Z

0

<?
if ($_GET['age'] > 18) 
{
    $page = 'a.php';
} else {
    $page = 'b.php';
}
include $page;
?>

<form>
   Age: <input type = "text" name="age">
   Submit: <input type="submit">
</form>

answered Aug 7, 2013 at 14:19

Your Common Sense

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6 Comments

Aris Over a year ago

how will he get age, before submitting?

user2541120 Over a year ago

where are you redirecting the user to page a or b

Orangepill Over a year ago

@amalmurali without action attribute form posts to itself.

eis Over a year ago

action attribute is required for HTML to be valid. However, it can be empty, so form will post to itself. Also, <? usually only works if shorttags are enabled - <?php is the standard way (and yes I know about php 5.4... )

Eve Over a year ago

But the server will give an error: Notice:Undefined index: age @Orangepill

|

anon · Accepted Answer · 2013-08-07 14:25:55Z

0

Submit the form to itself by leaving the action attribute empty:

<?php
if(isset($_POST['formSubmit'])) { //if form was submitted

    $age = $_POST['age'];

    if ($age > 18) 
    {
        header('Location: a.php');
    } else {
        header('Location: b.php');
    }

}
?>

<form method = "post" action"">
   Age: <input type = "text" name="age">
   Submit: <input type="submit" name="formSubmit">
</form>

answered Aug 7, 2013 at 14:25

anon

Comments

Fra H · Accepted Answer · 2013-08-07 14:38:36Z

Most likely you want to do it both in the current and in the target page.

Client side check

In the current page, you can use a javascript with a library like jQuery. Add an onclick event to your submit input, calling a function like:

<script type="text/javascript">
   $("input[type=submit]").click(function(event) {
     event.preventDefault(); // avoid normal action, actually not needed but useful sometimes
     if (parseInt($('input[type=text]').val()) < 18)
        $('form').attr('action', 'b.php');
     else $('form').attr('action', 'a.php');
     $('form').submit(); // due to the previous event.preventDefault()
});
</script>

That should do the trick. I suggest you to give ids to your inputs and change the above jQuery selectors accordly.

Server side check

Anyway, people could have javascript disabled or handly modified, so you can add a check even server side. For example, in a.php you can add:

if ((int)$_REQUEST['age'] < 18)
header('Location: b.php?age='.$_REQUEST['age']);

or anything better.

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