CODEWITHSUNDEEP
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NMenam
NMenam

Reputation: 134

Passing a "value" from a select in a form to a php variable with javascript issues

I'm trying to pass a value of a option in a select from my HTML form to a PHP variable through Javascript

<script type="text/javascript">
function changeDir(ID){
    var dir = document.getElementById(ID).value;
    //For debuging purposes i've used an alert to show the value of dir on screen
    //alert (dir);
    //At this point of the function I want to assign the value of "dir" to the variable $folder
    }
</script>

there's my .php with html

<SELECT name="course" ID="course" onchange='changeDir("course")' >
        <OPTION value="artes>'">artes</OPTION>
        <OPTION value="ingles">inglés</OPTION>
</SELECT>
<?php $folder= ...?>

I'm using this with a php upload lib, all working at the same file. If anyone can explain me how to assign the value of the option to a php var will be great.

Thanks and Regards.

Upvotes: 1

Views: 3957

Answers (2)

Gergely Rem&#233;nyi
Gergely Rem&#233;nyi

Reputation: 34

You can choose 2 different ways. First is AJAX, second is to redirect the page and GET the value of the <select> element.

HTML:

<SELECT name="course" ID="course" onchange='changeDir("course")' >
   <OPTION value="artes>'">artes</OPTION>
   <OPTION value="ingles">inglés</OPTION>
</SELECT>

JAVA:

<script type="text/javascript">
function changeDir(ID){
var dir = $("course").val();
$.post("php_file.php",
    {
      posted_dir: dir
    },
    function(data){
        $("id_of_result_elemnt").html(data);
    });
    }
</script

PHP:

<?php
$folder=$_POST['posted_dir'];
echo "This text will be display in the element with id_of_result_elemnt ID";
?>

Other method is redirect

HTML+PHP:

<SELECT name="course" ID="course" onchange='changeDir("course")' >
        <OPTION value="artes>'">artes</OPTION>
        <OPTION value="ingles">inglés</OPTION>
</SELECT>
<?php if (iset($_GET['folder']))
 {$_GET['folder']=$folder;}...?>

JAVA:

<script type="text/javascript">
function changeDir(ID){
    var dir = document.getElementById(ID).value;
    window.location = "http://example.com/myphp?folder=" + dir;
    }
</script>

Upvotes: 1

Diego Cardoso
Diego Cardoso

Reputation: 983

The fact is that you can't. They both live in different parts of your page. While you can write them in the same file, all PHP code is processed in the server side and Javascript is not able to see anything from the client side.

What you could do is whether pass it as a AJAX request in order to get back some information to show to the user or make the <select> refresh the page when user changes the option by submitting the form, so you don't lose the "state" of your form, and then verify in your php block if there's any option selected.

Upvotes: 1

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