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Drag And Drop(event) Not Trigger Ajax POST

- 1 answer

I have three pages: test.php, script.js, and main.php.

Main.php is using html5 drag and drop along with a simple ajax script from script.js, in an effort to post to- and activate test.php. (side note, i would like main.php to pass the <img id="s1" /> as a POST variable. After several hours of research and a hundred or so tests and revisions I am unable to figure out why I cannot get ondrop to trigger the post. Any advice would be greatly appreciated. Here is my code:

test.php (contains a simple php script that when loaded inserts a generic record into my DB)

script.js

function drop(id, event) {
   $.ajax({
        url: "test.php",
        type: "POST",
        data: {
            id: id,
            event: event
        },
        success: function () {
            console.log('great success');
            return true
        }
    });
    return false;
} 

and main.php

<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript" src="/js/jquery.js"></script>
<script type="text/javascript" src="/js/script.js"></script>
<header class="main-header" role="banner"><center>
  <img src="lampettalogo.jpg" height="90" width="400"alt="Banner Image"/></center>
</header>
<style>

#1 {width:auto;height:auto;padding:1px;border:1px solid #aaaaaa;}
#2 {width:auto;height:auto;padding:1px;border:1px solid #aaaaaa;}
#3 {width:auto;height:auto;padding:1px;border:1px solid #aaaaaa;}
#4 {width:auto;height:auto;padding:1px;border:1px solid #aaaaaa;overflow: auto;}
</style>

</head>
<body>
<div id="1" ondrop="drop(event)" ondragover="allowDrop(event)">
<?php 
include "database_connection.php";
///////////////////////////////////////////////////////////////////////////////////////////////
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
else
{
}
$query = "SELECT * FROM ss where currentZone = 1";
if ($result = mysqli_query($link, $query)) {
    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {
        echo "<img id='{$row["sID"]}' src='{$row["photoLink"]}.jpg' draggable='true' ondragstart='drag(event)' width='75' height='75'>"  ;
    }
    /* free result set */
    mysqli_free_result($result);
}
 mysqli_close($link);
 /////////////////////////////////////////////////////////////////////////////////
?>
</div>
<div id="2" ondrop="drop(event)" ondragover="allowDrop(event)">
<?php
include "database_connection.php";
$query = "SELECT * FROM ss where currentZone = 2";
if ($result = mysqli_query($link, $query)) {
    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {        
        echo "<img id='{$row["sID"]}' src='{$row["photoLink"]}.jpg' draggable='true' ondragstart='drag(event)' ondrop='drop(event)' width='75' height='75'>"  ;
    }
    /* free result set */
    mysqli_free_result($result);
}
 mysqli_close($link);
?>
</div>
<div id="3" ondrop="drop(event)" ondragover="allowDrop(event)">
<?php
include "database_connection.php";
$query = "SELECT * FROM ss where currentZone = 3";
if ($result = mysqli_query($link, $query)) {
    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {        
        echo "<img id='{$row["sID"]}' src='{$row["photoLink"]}.jpg' draggable='true' ondragstart='drag(event)' width='75' height='75'>"  ;
    }
    /* free result set */
    mysqli_free_result($result);
}
 mysqli_close($link);
?>
</div>
<div id="4" ondrop="drop(event)" ondragover="allowDrop(event)">
<?php
include "database_connection.php";
$query = "SELECT * FROM ss where currentZone = 4";
if ($result = mysqli_query($link, $query)) {
    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {        
        echo "<img id='{$row["sID"]}' src='{$row["photoLink"]}.jpg' draggable='true' ondragstart='drag(event)' width='75' height='75'>"  ;
    }
    /* free result set */
    mysqli_free_result($result);
}
 mysqli_close($link);
?>
</div>
<div id="4" ondrop="drop(event)" ondragover="allowDrop(event)">
<?php
include "database_connection.php";
$query = "SELECT * FROM ss where currentZone = 0";
if ($result = mysqli_query($link, $query)) {
    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {        
        echo "<img id='{$row["sID"]}' src='{$row["photoLink"]}.jpg' draggable='true' ondragstart='drag(event)' width='75' height='75'>"  ;
    }
    /* free result set */
    mysqli_free_result($result);
}
 mysqli_close($link);
?>
</div>
</body>
</html>
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Answer

In your drop(id, e) method, you can consider the following, in addition to your allowDrop method. Use the FileReader class to read your file.

function drop(id, e) {
  if (e.dataTransfer && e.dataTransfer.files.length != 0) {
    var file = e.dataTransfer.files[0], // Only the first file.
      reader = new FileReader();

    reader.readAsDataURL(file);

    reader.onload = function (event) {
      console.log(file.name);
      $.ajax({
        url: "test.php",
        type: "POST",
        data: {
          id: id,
          fileName: file.name, // Your file name.
          file: event.target.result // Your file.
        },
        success: function () {
          console.log('great success');
          return true
        }
      });
    };
  }
}

And in your HTML, you need to pass a value in id as well. For example, you can do the following to print out your $row["sID"] into the method parameter.

<div id="1" ondrop="drop('<?php echo $row["sID"]; ?>', event)" ondragover="allowDrop(event)">

On your PHP script, you need to be able to receive the POSTed file. An example is shown below.

$data = $_POST['file'];
$fileName = $_POST['fileName'];
$id = $_POST['id'];

$serverFile = $fileName . "-" . time(); // Appends timestamp so that files of the same name wouldn't be overwritten.
$fp = fopen('/uploads/' . $serverFile, 'w');
fwrite($fp, $data);
fclose($fp);
$returnData = array( "serverFile" => $serverFile );
echo json_encode($returnData);

See this plunker for an example. Drop a file into the div, and watch the console log.


Edit

Understood that you want to drag and drop elements instead.

Below is the updated plunker.

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source: stackoverflow.com
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