一個隨意改變形狀JS插件：interact.js

interact.js是一個隨意改變形狀插件,它非常強大的，靈活拖放，改變大小，支持現代瀏覽器的多點觸摸手勢，基于SVG的運用，能運行在包括在IE8+的瀏覽器.

• inertia
• snapping to a grid, custom anchors or paths.
• cross browser and device, supporting the desktop and mobile versions of Chrome, Firefox and Opera as well as Internet Explorer 8+
• interaction with SVG elements
• being lightweight and standalone (not yet another jQuery plugin)
• not modifying anything it doesn't own (except to support IE8 and to change the cursor (but you can disable that))
</ul>

示例：

var // x and y to keep the position that's been dragged to
    x = 0,
    y = 0,
    // vendor prefixes (prefices?)
    transformProp = 'transform' in document.body.style?
                'transform': 'webkitTransform' in document.body.style?
                    'webkitTransform': 'mozTransform' in document.body.style?
                        'mozTransform': 'oTransform' in document.body.style?
                            'oTransform': 'msTransform';

// make an Interactable of the document body element
interact(document.body)
    // make a draggable of the Interactable
    .draggable({
        // on(drag)move
        // could also have done interact(document.body).draggable(true).ondragmove = function...
        onmove: function (event) {
            x += event.dx;
            y += event.dy;

            // translate the document body by the change in pointer position
            document.body.style[transformProp] = 'translate(' + x + 'px, ' + y + 'px)';
        }
    })
    // you should really add listeners like this if you want to add multiple listeners
    .on('dragend', function (event) {
        console.log('dragged a distance of ' + 
            Math.sqrt(event.dx*event.dx + event.dy*event.dy) + 
            ' pixels to ' + event.pageX + ', ' + event.pageY);
    })
    // allow inertia throwing
    .inertia({
        resistance: 15,
        zeroResumeDelta: true
    })
    // snap to the corners of the specified grid
    .snap({
        mode: 'grid',
        grid: {
            x: 100,
            y: 5
        },
        gridOffset: {
            x: 20,
            y: 10
        },
        range: Infinity // can also use -1 which gets changed to Infinity
    });


// you can also listen to InteractEvents for every Interactable
interact.on('dragstart', function (event) {
    console.log('starting drag from ' + event.x0 + ', ' + event.y0);
});

項目主頁：http://www.baiduhome.net/lib/view/home/1417057975159