Upload multiple files with the file dialog or by dragging and dropping images onto the dashed region Technically this isn’t necessary, but it’s a good idea to provide it as an alternative in case the user has a browser without support for the drag-and-drop API. Setting Up Our Formīefore we start adding drag-and-drop functionality, we’ll need a basic form with a standard file input. If you don’t, the browser will end up opening the file you dropped instead of sending it along to the drop event handler. The drop event will propagate up to dropArea (unless propagation is stopped by a different event listener before it gets there), so it’ll still fire on dropArea despite it not being the target for the event.Īlso note that in order to create custom drag-and-drop interactions, you’ll need to call event.preventDefault() in each of the listeners for these events. Note that the dragged item is dragged over a child of dropArea, dragleave will fire on dropArea and dragenter will fire on that child element because it is the new target.
The user releases their mouse button, dropping the dragged item onto dropArea. The dragged item is dragged off of dropArea and onto another element, making it the target for the drop event instead.Įvery few hundred milliseconds, while the dragged item is over dropArea and is moving. The dragged item is dragged over dropArea, making it the target for the drop event if the user drops it there.
#Dropzone input file code#
Here’s a little table describing what these events do, using dropArea from the code sample in order to make the language clearer: Event Let dropArea = document.getElementById('drop-area')ĭropArea.addEventListener('dragenter', handlerFunction, false)ĭropArea.addEventListener('dragleave', handlerFunction, false)ĭropArea.addEventListener('dragover', handlerFunction, false)ĭropArea.addEventListener('drop', handlerFunction, false) If you’re curious about them, you can read some documentation about these events on MDN. We won’t be going over all of them because drag, dragend, dragexit, and dragstart are all fired on the element that is being dragged, and in our case, we’ll be dragging files in from our file system rather than DOM elements, so these events will never pop up. In all, there are eight events the browser fires related to drag and drop: drag, dragend, dragenter, dragexit, dragleave, dragover, dragstart, and drop. The first thing we need to discuss is the events related to drag-and-drop because they are the driving force behind this feature. Here’s a quick look at what you’ll be making: A demonstration of a web page in which you can upload images via drag and drop, preview the images being uploaded immediately, and see the progress of the upload in a progress bar.
#Dropzone input file plus#
This example - aside from the ES2015+ syntax, which can easily changed to ES5 syntax or transpiled by Babel - should be compatible with every evergreen browser plus IE 10 and 11. In this article, we’ll be using “vanilla” ES2015+ JavaScript (no frameworks or libraries) to complete this project, and it is assumed that you have a working knowledge of JavaScript in the browser.
So, let’s actually use the APIs given to us by the browser to implement a drag-and-drop file selector and uploader. Technically, this was already possible because most (if not all) implementations of the file selection input allowed you to drag files over it to select them, but this requires you to actually show the file element. Nowadays, though, we have an even fancier way of handling file selection: drag and drop. It’s a known fact that file selection inputs are difficult to style the way developers want to, so many simply hide it and create a button that opens the file selection dialog instead. This example should be compatible with every evergreen browser plus IE 10 and 11.
In this article, we’ll be using “vanilla” ES2015+ JavaScript (no frameworks or libraries) to complete this project, and it is assumed you have a working knowledge of JavaScript in the browser.
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