How to make a PHP 'if' code work when using auto submit with Java Script?

Question

I have a file upload form that I want to be submited automatically when the file has been selected. I am using Javascript onchange event to do it.

<form action="form.php" method="post" enctype="multipart/form-data">
<input type="file" name="filename" onchange="javascript:this.form.submit();">
</form>

This code seems to work as it is, but I have a PHP if statement that processes the file uploaded when a $_POST['submit'] happens (using the the submit button)

<?php
        if(isset($_POST['submit'])){
            $photo = Photograph::find_by_userid($user_id);
            $photo = new Photograph();
            $photo->attach_file($_FILES['photo_upload']);

           }
        ?>

But since the point of this is to remove the submit button <input type="submit" name="submit"/> the PHP if code is not being triggered, ergo the file is not being uploaded. Do you know how can I make the if statement work when not using a submit button and using an auto submit with Javascript?

Thanks in advance!

This is the whole code..

<?php require_once("../includes/initialize.php"); ?>
<?php include_layout_template("header.php"); ?>
<?php include_layout_template("edit_header.php"); ?>

<?php

if(!$session->is_logged_in()){
    redirect_to("login.php");
    }else{

    }
    $id=$session->user_id;
    $user=User::find_by_id($id);
    $user_id = $user->id;



    if(isset($_POST['submit'])){
        $photo = Photograph::find_by_userid($user_id);
        if($photo){
            $photo->destroy();
            $photo = new Photograph();
        $photo->user_id = $user_id;
        $photo->attach_file($_FILES['photo_upload']);
        if($photo->save()){
            redirect_to("edit_photo.php");
            $session->message = "Photo uploaded succesfully";
        } else{
            $message = join("<br/>", $photo->errors);
        }
        }

        $photo = new Photograph();
        $photo->user_id = $user_id;
        $photo->attach_file($_FILES['photo_upload']);
        if($photo->save()){
            redirect_to("edit_photo.php");
            $session->message = "Photo uploaded succesfully";
        } else{
            $message = join("<br/>", $photo->errors);
        }

    }

     $photo = Photograph::find_by_userid($user_id);

?>


<section class="edit_section">
<h2>Upload/Change <br/> Your Photo</h2>
<p><?php echo form_errors($errors); ?></p>
<p class="messages"><?php echo $message ?></p>

<form class="edit_form" id="form" action="edit_photo.php" enctype="multipart/form-data" method="POST">

<input type="hidden" name="MAX_FILE_SIZE" value="1048576" />
<ul>
<li>
<img src="<?php if(isset($photo)){echo $photo->image_path();} ?>"  width="250px" />
<label for="photo_upload">Upload/Change <br/> your photo</label>
<input type="file" id="photo_upload" name="photo_upload" style="background:none; border:none;" value="upload" onchange="javascript:this.form.submit();"/>


<!--input type="submit" name="submit" value="Upload" /-->
</li>

</ul>
</form>
<section style="margin-left: 400px;" >
<p class="button"><a href="delete_photo.php?id=<?php if(isset($photo)) {echo $photo->id; }?>">Delete it</a></p>
</section>
</section>
<?php include_layout_template("footer.php"); ?>

I think you might be better off using jQuery/AJAX rather than JS form submit logic. — Maximus2012
– Maximus2012, Commented Jun 10, 2015 at 21:56

Jose Manuel Abarca Rodríguez · Accepted Answer · 2015-06-10 22:14:18Z

2

One solution is to add a hidden field to the form, this field will be recognized by PHP, for example, let's call it "my_flag" :

<form action="form.php" method="post" enctype="multipart/form-data">
  <input type="file" name="filename" onchange="javascript:this.form.submit();">
  <input type="text" name="my_flag" hidden />
</form>

Now, on the PHP side, you do :

<?php
if ( isset( $_POST['my_flag'] ) )
   echo "flag";
?>

The echo "flag"; is just for testing, you replace it by your code.

answered Jun 10, 2015 at 22:14

Jose Manuel Abarca Rodríguez

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1 Comment

Arturo Rosales Baez Over a year ago

Thanks so much @Jose Manuel Abarca Rodriguez it worked like a charm!

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