HTML5 - Drag and Drop

Drag and drop is a part of the HTML5 standard.

Drag and Drop

Drag and drop is a very common feature. It is when you "grab" an object and drag it to a different location.
In HTML5, drag and drop is part of the standard, and any element can be draggable.

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Browser Support

Internet Explorer 9+, Firefox, Opera, Chrome, and Safari support drag and drop.
Note: Drag and drop does not work in Safari 5.1.2.

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HTML5 Drag and Drop Example

The example below is a simple drag and drop example:
It might seem complicated, but lets go through all the different parts of a drag and drop event.

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Make an Element Draggable

First of all: To make an element draggable, set the draggable attribute to true:

<img draggable="true">

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What to Drag - ondragstart and setData()

Then, specify what should happen when the element is dragged.
In the example above, the ondragstart attribute calls a function, drag(event), that specifies what data to be dragged.
The dataTransfer.setData() method sets the data type and the value of the dragged data:

function drag(ev)
{
ev.dataTransfer.setData("Text",ev.target.id);
}

In this case, the data type is "Text" and the value is the id of the draggable element ("drag1").

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Where to Drop - ondragover

The ondragover event specifies where the dragged data can be dropped.
By default, data/elements cannot be dropped in other elements. To allow a drop, we must prevent the default handling of the element.
This is done by calling the event.preventDefault() method for the ondragover event:

event.preventDefault()

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Do the Drop - ondrop

When the dragged data is dropped, a drop event occurs.
In the example above, the ondrop attribute calls a function, drop(event):

function drop(ev)
{
ev.preventDefault();
var data=ev.dataTransfer.getData("Text");
ev.target.appendChild(document.getElementById(data));
}

Code explained:

• Call preventDefault() to prevent the browser default handling of the data (default is open as link on drop)
• Get the dragged data with the dataTransfer.getData("Text") method. This method will return any data that was set to the same type in the setData() method
• The dragged data is the id of the dragged element ("drag1")
• Append the dragged element into the drop element