Swiper code snippet from http://jsfiddle.net/timwhitlock/2vJDs/

swiper.js

/**
 * swipe inertia demo for browsers supporting the touchstart family of events
 * @param HTMLElement
 * @param Function touchend callback with speed and direction of swipe
 */
function initSwiper( el, callback ){
    var xstart  = 0,  // <- initial scroll position on first touch
        tstarts = [], // <- time each touch started
        xoffset = [], // <- initial x position of each touch
        yoffset = []; // <- initial y position of each touch

    /**
     * Utility for getting current time in milliseconds
     */
    var now = Date.now || function(){
        return new Date().getTime();
    };        

    /**
     * Initialize swipe on touchstart
     */
    function onTouchStart( event ){
        var t = now();
        eachTouchEvent( event, function( i, e ){
            tstarts[i] = t;
            xoffset[i] = e.clientX;
        } );
        xstart = el.scrollLeft;
        return true;
    }

    /**
     * Callback for touchmove
     */
    function onTouchMove( event ){
       var xmove, ymove;
       eachTouchEvent( event, function( i, e ){
            xmove = xoffset[i] - e.clientX;
            ymove = yoffset[i] - e.clientY;
       } );
       if( ymove && Math.abs(ymove) > Math.abs(xmove) ){
           // this was intended as a vertical scroll - probably of the page
           // we will allow this event through so the OS/browser can handle it.
           return true;
       }
       if( xmove ){
           // else take control of horizonal scroll and cancel event
           el.scrollLeft = Math.max( 0, xstart + xmove );
       }
       event.preventDefault();
       return false;
    }

    /**
     * Callback when touch released
     */
    function onTouchEnd( event ){
        eachTouchEvent( event, function( i, e ){
            var touchtime  = now() - tstarts[i],
                touchmoved = xoffset[i] - e.clientX,
                speed = Math.abs( touchmoved ) / touchtime,
                direction = touchmoved ? ( touchmoved < 0 ? -1 : 1 ) : 0;
            callback( speed, direction );
        } );
        return true;
    }

    /**
     * multi-touch iterator
     */
    function eachTouchEvent( event, callback ){
        var i = -1, 
            touched = event.originalEvent || event,
            changed = touched.changedTouches||[];
        while( ++i < changed.length ){
            callback( i, changed[i] );
        }    
    }
    
    // bind standard touch events
    el.addEventListener('touchstart', onTouchStart, false );
    el.addEventListener('touchmove', onTouchMove, false );
    el.addEventListener('touchend', onTouchEnd, false );
}