var dd = $(".drag_bott").removeAttr('id').last().attr('id','drag_bott');

var drag = document.getElementById("drag_bott");

function moveButton(){

    obj = this;

    var intX = event.targetTouches[0].pageX;//点击的X坐标

    var intY = event.targetTouches[0].pageY;//点击的Y坐标

    var right = $(obj).css('left');

    var bottom = $(obj).css('bottom');

    obj.addEventListener('touchmove', function(){

        event.preventDefault();

        var moveX = event.targetTouches[0].pageX;//动态获取鼠的X坐标

        var moveY = event.targetTouches[0].pageY;//动态获取鼠的Y坐标

        var disX = intX-moveX;//差值

        var disY = moveY-intY;//差值

        var movX = parseInt(right)-disX+'px';//目标right值

        var movY = parseInt(bottom)-disY+'px';//目标bottom值

        $(obj).css('left',movX);

        $(obj).css('bottom',movY);

    });

};

drag.addEventListener('touchstart',moveButton,false);