how to send multiple values to PHP using "onchange="?

Question

I have two radio button categories: color1 and color2. Color 1 can be either black or white and color 2 can be either red or blue. I just want the user to be able to pick from just one category or both categories and then echo out the choices with PHP.

My problem is that it will not echo out choices from both categories at the same time. For example, if I click the "white" radio button and then click the "blue" radio button, it will only echo out "blue", not both "white" and "blue".

UPDATE:

<?php
session_start();

if(isset($_GET['color1'])){
  $_SESSION['color1'] = $_GET['color1'];
}

if(isset($_GET['color2'])){
  $_SESSION['color2'] = $_GET['color2'];
}

echo $_SESSION['color1']; 
echo $_SESSION['color2'];
?>


select first color:<br/>
<input type="radio" name="color1" value="black" onchange="window.location.href='recom.php?color1='+this.value"> black<br />

<input type="radio" name="color1" value="white" onchange="window.location.href='recom.php?color1='+this.value">  white<br />

select second color:<br/>
<input type="radio" name="color2" value="red" onchange="window.location.href='recom.php?color2='+this.value"> red<br />

<input type="radio" name="color2" value="blue" onchange="window.location.href='recom.php?color2='+this.value">  blue

Luke · Accepted Answer · 2011-06-24 00:15:45Z

4

You need to send both variables to when you are doing request (just as shown in answer by yes123).

Or you can use $_SESSION in your PHP to keep a state of what has been selected and hasn't.

You can read on sessions here http://www.tizag.com/phpT/phpsessions.php

Session is just an array (i'm keeping it very simple). You can put some values in that array and each time page is reloaded those values will stick around - unless you close your browser window.

In your case

session_start(); // Remember to have this on top of your php file before any echo or print or any other html is printed out.

if(isset($_GET['color1']){
  $_SESSION['color1'] = $_GET['color1'];
}

if(isset($_GET['color2']){
  $_SESSION['color2'] = $_GET['color2'];
}

echo $_SESSION['color1']; 
echo $_SESSION['color2'];

I would also suggest not using "red", "blue" etc.

Give each colour an id - red = 1, blue = 5 etc.

Then you do $_SESSION['color2'] = intval($_GET['color2']); This means that you store your colours as numbers which are easy to sanitize with intval(). When you need to display which colour has been selected you can just write a method that takes a number and returns a string with colour. (simple switch statement). That will stop people from injecting your html with some garbage.

function get_colour($i){
  switch(intval($i)){
    case 1:
      $colour = "blue";
      break;
    case 2:
      $colour = "red";
      break;
    default:
      $colour = "blue"; // default colour when people try to fiddle with injection
      break;
  }
  return $colour;
}

edited Jun 24, 2011 at 0:15

answered Jun 23, 2011 at 23:29

Luke

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7 Comments

user701510 Over a year ago

can you give an example of how to use $_SESSION with my situation?

user701510 Over a year ago

hmm it's still not echoing both categories. Please see my updated OP.

Luke Over a year ago

@user701510 Can you refer to stackoverflow.com/questions/6300160/sessionuser-not-working/… in answer i have described how to test for any issues with sessions or do a check if they work. Also can you provide me with var_dump($_SESSION, $_GET) to make sure that session is actually kept from request to request as well as you are passing right. Does it show just one category still or not showing anything at all?

user701510 Over a year ago

var_dump($_SESSION, $_GET) gets me array(2) { ["color1"]=> string(5) "black" ["color2"]=> string(4) "blue" } array(1) { ["color1"]=> string(5) "black" } but after that, if I click any other color, nothing happens.

Luke Over a year ago

@user701510 hmm.. vardump is showing correctly that there is color1 and color2 in $_SESSION and one variable in $_GET which is correctly. So i can think of only two things that are going wrong. a) You are changing somehow $_SESSION['colorX'] before you echo it b) You have spelling somewhere when you do echo?

|

dynamic · Accepted Answer · 2011-06-23 23:25:23Z

1

onchange=" window.location.href='recom.php?color1='+this.value+'
           &color2='+document.getElement[..]
         "

Also consider to use jQuery

answered Jun 23, 2011 at 23:25

dynamic

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Comments

Kinjal Dixit · Accepted Answer · 2011-06-23 23:27:37Z

1

you can put both radio buttons in a form, and in both onchange events, just submit the form.

answered Jun 23, 2011 at 23:27

Kinjal Dixit

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Comments

Brian Patterson · Accepted Answer · 2011-06-24 01:41:04Z

0

Just use a class ...

<input type="radio" name="color1" value="black"  class="myElementClass"> Black <br />
<input type="radio" name="color2" value="white"  class="myElementClass"> White <br />


Jquery {


    $(.myElementClass).change(function() {

    //do whatever i want
    });

}

answered Jun 24, 2011 at 1:41

Brian Patterson

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Comments

Devin Burke · Accepted Answer · 2012-01-10 18:10:30Z

0

try something like this:

select first color:<br/>
<input type="radio" name="color1" value="black" onchange="window.location.href='<?php if(isset($_GET['color2'] echo"\'recom.php?color1=\'+this.value+\'&color2=".$_GET['color2'];else echo"\'recom.php\'+this.value";?>> black<br />

edited Jan 10, 2012 at 18:10

Devin Burke

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answered Jun 30, 2011 at 11:33

Abhishek Bhatia

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