js实现可拖动的图片

<img src="Images/book.jpg" border="0" alt="test" style='position: absolute;' ondragstart='setCapture();xx=event.x-this.offsetLeft;yy=event.y-this.offsetTop;'
        ondrag='this.style.left=event.x-xx;this.style.top=event.y-yy' ondragend='releaseCapture();' />