draggable

High performance, fully cross browser, full featured drag and drop in a tiny (2k gzipped), dependency-free package.

Demo

http://bcherny.github.io/draggable/demos/basic/

Usage

HTML

<div id="id"></div>

JavaScript

Using browser globals:

var element = document.getElementById('id');
var options = {
  grid: 10,
  onDrag: function(){ ... }
};
new Draggable (element, options);

Using AMD/CommonJS:

var Draggable = require ('Draggable');
var element = document.getElementById('id');
new Draggable (element);

Dependencies

None!

Options

| Option | Type | Default | Description | |-------------------|---------------------|---------|-----------------------------------------------------------------------| | grid | Number | 0 | grid size for snapping on drag | | handle | Element | null | the handle of the draggable; if null, the whole element is the handle | | filterTarget | Function(target) | null | prevent drag when target passes this test | | limit | Element, Function(x, y, x0, y0), or Object | { x: null, y: null } | limit x/y drag bounds | | threshold | Number | 0 | threshold before drag begins (in px) | | setCursor | Boolean (truthy) | false | change cursor to move? | | setPosition | Boolean (truthy) | true | change draggable position to absolute? | | smoothDrag | Boolean (truthy) | true | snap to grid only when dropped, not during drag | | useGPU | Boolean (truthy) | true | move graphics calculation/composition to the GPU? (modern browsers only, graceful degradation) |

Events

| Event | Arguments | |-----------------|-------------------------| | onDrag | element, x, y, event | | onDragStart | element, x, y, event | | onDragEnd | element, x, y, event |

Instance methods

| Method | Arguments | Returns | Description |---------------|-----------------------------------------|-----------------------|-------------------------------------------| | get | --- | {Object} {x, y} | Get the current coordinates | | set | {Number} x, {Number} y | instance | Move to the specified coordinates | | setOption | {String} property, {Mixed} value | instance | Set an option in the live instance | | destroy | --- | --- | Unbind the instance's DOM event listeners |

Notes

Options.limit accepts arguments in several forms:

// no limit
limit: null

// limit x, but leave y unbounded
limit: {
  x: [1,10],
  y: null
}

// limit both axes
limit: {
  x: [1,10],
  y: [1,500]
}

// bound x, set y to a constant
limit: {
  x: [1,10],
  y: 5
}

// bound with an element
limit: document.getElementById('id')

// bound with a custom function
limit: function (
  x,  // current X coordinate
  y,  // current Y coordinate
  x0, // original X coordinate (where drag was started)
  y0  // original Y coordinate (where drag was started)
) {

  var radius = 100,
    dx = x - x0,
    dy = y - y0,
    distance = Math.sqrt(dx*dx + dy*dy),

    // only allow dragging within a circle of radius 100
    outOfRange = distance > radius;


  // if our point is outside of the circle, compute the
  // point on the circle's edge closest to our point
  if (outOfRange) {

    x = x0 + radius * (x - x0) / distance;
    y = y0 + radius * (y - y0) / distance;

  }

  return {
    x: x,
    y: y
  };

}

Tested on

• Chrome 29 on OSX
• Chrome 28 on Windows
• Firefox 23 on OSX
• Firefox 21 on Windows
• Opera 16 on OSX
• Safari 6 on OSX
• Safari 6 on iPhone4/iOS6
• Safari 6 on iPhone5/iOS6
• Safari 6 on iPad2/iOS6
• Safari 6 on iPad3/iOS6
• Internet Explorer 8-10 on Windows

To do

• Improve performance on old iOS
• Unit tests