Self-study HTML5 section III (Drag and drop effect)

Take a look at the drag-and-drop effect on the web today, and first look at what drag-and-drop ————

Drag and drop

Drag-and-drop is a common feature that grabs an object and then drags it to another location.

In HTML5, drag-and-drop is part of the standard, and any element can be dragged and dropped.

Browser support

Internet Explorer 9, Firefox, Opera 12, Chrome, and Safari 5 support drag and drop.

Note: Drag-and-drop is not supported in Safari 5.1.2

HTML code:

<! DOCTYPE html>
Set elements to be dragged and dropped
First, to make the element draggable, set the element to be dragged, such as the Draggable property in the img tag element to true:
Then, specify what happens when the element is dragged.
In the example above, the Ondragstart property invokes a function, drag (event), which specifies the data to be dragged.
The Datatransfer.setdata () method sets the data type and value of the dragged data:
function drag (EV) {ev.dataTransfer.setData ("Text", ev.target.id);     In this example, the data type is "Text" and the value is the ID of the draggable element ("Drag1").
}
The OnDragOver event specifies where to place the dragged data.
By default, data/elements cannot be placed in other elements. If you need to set allow placement, we must block the default handling of elements.
This is done by invoking the event for OnDragOver events  . Preventdefault () Method:
Event.preventdefault ()    //Call Preventdefault () to avoid browser default handling of data (the default behavior of the drop event is to open as a link)
The drop event occurs when the dragged data is dropped.
In the example above, the OnDrop property invokes a function, drop (event):
function Drop (EV) {ev.preventdefault (); var data=ev.datatransfer.getdata ("Text");     The dragged data is obtained by means of the Datatransfer.getdata ("Text") method. The method returns any data that is set to the same type in the SetData () method.
Ev.target.appendChild (document.getElementById (data));   }
Self-study HTML5 section III (Drag and drop effect)