PHP variable as form action

Question

I want to make a form whose action is defined by one of the options in the form.

    <form method="POST" action="../<?php echo $location?>.php">
    <label>Post to: <select project="location" id="location" name="location">
        <option value="null"></option>
        <option value="$var1">Option1</option>
        ...
    </select><br>
    <input id ="button1" type="submit" name="submit" value="Post">
</form>
<?php $location = $_POST["location"]; ?>

It keeps using an empty value for location when the submit button is clicked; is there any way for it to store the value of $location before the form chooses where to post?

So you are asking how to change a form's action live (without server reload) depending on a selected option. Sounds much more like a JavaScript question to me - do you have any experience in that field? — kero
– kero, Commented Jul 22, 2015 at 0:32
I don't know much about JavaScript but I could look into it; would I be able to maintain the current form? — djswizzy
– djswizzy, Commented Jul 22, 2015 at 0:42
Move the <?php $location = $_POST["location"]; ?> to just before the form element BUT if the variable is dependent on the current page values then the first time through $location will always be blank because it hasn't bee set yet. — user2417483
– user2417483, Commented Jul 22, 2015 at 0:46
Are you trying to submit the form to it's current page? What's the value of the action? — Jerielle
– Jerielle, Commented Jul 22, 2015 at 0:49

danopz · Accepted Answer · 2015-07-22 01:23:10Z

3

No.

PHP is executed on the Server. When you post this form PHP only know content of that variable when post is there. So on first-rendering the page the variable of course is empty.

But you could do this with Javascript:

<form id="postForm" method="POST" action="">
    <label>
        Post to:
        <select project="location" id="location" name="location">
            <option value="first"></option>
            <option value="handle-something">Option1</option>
        </select>
    </label>
    <input id="button1" type="submit" name="submit" value="Post">
</form>

<script>
    document.getElementById('location').onchange = function() {
        // maybe you can get val via this or so
        var location = document.getElementById('location').value;
        document.getElementById('postForm').action = '/' + value + '.php';
    };
</script>

Not testet.

edited Jul 22, 2015 at 1:23

answered Jul 22, 2015 at 0:42

danopz

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Comments

Daniel · Accepted Answer · 2015-07-22 01:04:26Z

While you can generate the form dynamically on render, you cannot change it with php after the form is served. You will need to use javascript for that as @copynpaste already shows. There is another option you can use.

Send the form to a standard action and extract your variable on the server-side where you decide what to do.

example:

<form method="POST" action="formaction.php">
        <label>Post to: <select project="location" id="location" name="location">
            <option value="null"></option>
            <option value="$var1">Option1</option>
            ...
        </select><br>
        <input id ="button1" type="submit" name="submit" value="Post">
</form>

Inside formaction.php

$action = $_POST['action'];

include "{$action}.php";

This will include a file based on the value of "location".

unrivaledcreations · Accepted Answer · 2015-07-22 03:00:16Z

Since it's unlikely that you would want to allow post data to go to a potentially arbitrary, uncontrolled file location based upon unsanitized post data, I like the idea of examining the data's values for acceptable values; then applying a 'default' catch-all to address two cases: (1) a situation where the form is loaded without post data; and (2) a situation where the form is loaded with unanticipated or unacceptable post data:

<?php 
    $location = $_POST["location"];
    switch( $location )
    {
        case 'create':
        case 'remove':
        case 'update':
        case 'delete':
            $form_location = $location;
            break;
        default:
            $form_location = 'default';
            break;
    }
?>
<form method="POST" action="../<?php echo $form_location; ?>.php">
    <label>Post to: <select project="location" id="location" name="location">
    <option value="null"></option>
    <option value="$var1">Option1</option>
    ...
    </select><br>
    <input id ="button1" type="submit" name="submit" value="Post">
</form>

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