HTML5 Drag and Drop - Firefox is being redirected

javascript html firefox drag-and-drop

10,343

function drop(e) {
    if(e.preventDefault) { e.preventDefault(); }
    if(e.stopPropagation) { e.stopPropagation(); }
    window.draggedIcon.element.style.left = (event.clientX + window.draggedIcon.offset[0]) + 'px';
    window.draggedIcon.element.style.top  = (event.clientY + window.draggedIcon.offset[1]) + 'px';
    window.draggedIcon.element.style.visibility = 'visible';
    window.draggedIcon.element = null;
    return false;
}

10,343

Author by

m93a

Licensing note: All original code snippets I post on StackOverflow and other Stack Exchange sites are licensed under the CC0 Public Domain Dedication – do with them as you see fit.

Updated on July 16, 2022

Comments

m93a almost 2 years

I'm trying to implement html5's drag and drop in my app but Firefox is always redirected to dropped image's source. I'm using e.stopPropagation(). In Chromium everything works as expected. Strange... Here's the code:

<html>
 <head>
  <meta charset="utf-8" />
  <title>DuOS 0.0.0</title>
  <meta name="author" content="Jan Durrer, Michal Grňo" />
  <link rel="stylesheet" href="./default.css" />
 </head>
 <body>
  <script src="./boot.js"></script>
  <script src="./window.js"></script>
  <script src="./omnibox.js"></script>
  <section class="desktop">
   <img class="icon" id="computer" style="left: 0px; top: 340px;" src="./image/icon/system/computer.png" />
   <img class="icon" id="folder" style="left: 0px; top: 170px;" src="./image/icon/system/documents.png" />
   <img class="icon" id="bin" style="left: 0px; top: 0px;" src="./image/icon/system/bin.png" />
  </section>
  <script>
   window.clickedIcons = Array();
   window.draggedIcon = {};
   window.draggedIcon.offset = Array();
   window.draggedIcon.element = null;

   //Pohybování
   function drag_start(e) {
    window.draggedIcon.element = e.target;
    event.dataTransfer.effectAllowed = 'copyMove';
    event.dataTransfer.setData('text/plain', 'hola'); //hack

    var style = window.getComputedStyle(event.target, null);
    window.draggedIcon.offset[0] = parseInt(style.getPropertyValue("left"),10) - event.clientX; console.log(window.draggedIcon.offset[0]);
    window.draggedIcon.offset[1] = parseInt(style.getPropertyValue("top" ),10) - event.clientY; console.log(window.draggedIcon.offset[1]);
    window.draggedIcon.element = event.target;
   }

   function drag_over(e) {
    e.preventDefault();
    return false;
   }

   function drop(e) {
    window.draggedIcon.element.style.left = (event.clientX + window.draggedIcon.offset[0]) + 'px';
    window.draggedIcon.element.style.top  = (event.clientY + window.draggedIcon.offset[1]) + 'px';
    window.draggedIcon.element.style.visibility = 'visible';
    window.draggedIcon.element = null;
    if(e.stopPropagation) {e.stopPropagation();}
    return false;
   }
   var xresult = document.evaluate('//body/*[@class="desktop"]/*[@class="icon"]', document, null, XPathResult.ANY_TYPE, null);
   var dm = xresult.iterateNext();
   while (dm) {
    dm.addEventListener('dragstart',drag_start,false);
    dm.addEventListener('click',click,false);
    dm = xresult.iterateNext();
   }

   document.body.addEventListener('dragover',drag_over,true);
   document.body.addEventListener('drop',drop,true);
  </script>
 </body>
</html>

Thanks for your help, m93a.

Matthieu Riegler over 4 years

preventDefault does the job ! But could someone explain me why a drop would trigger a redirect on Firefox ??
awendt about 3 years

@MatthieuRiegler Wild guess: Dropping a file into Firefox navigates to the file, that's why the default is navigate to the URL being dropped. In my case, drag had called event.dataTransfer.setData('text/plain', "css") before and FF attempted to open the URL "css".