Vue.directive('tap',{

    bind:function(el,binding){

        var startTx, startTy, endTx, endTy, startTime, endTime;

        el.addEventListener("touchstart",function(e){

            var touch=e.touches[0];

            startTx = touch.clientX;

            startTy = touch.clientY;

            startTime = +new Date()

        },false );

        el.addEventListener("touchend",function(e){

            endTime = +new Date()

            if (endTime - startTime > 300) {

                // 若点击事件过长，不执行回调

                return

            }

            var touch = e.changedTouches[0];

            endTx = touch.clientX;

            endTy = touch.clientY;

            if( Math.abs(startTx - endTx) < 6 && Math.abs(startTy - endTy) < 6){

                // 若点击期间手机移动距离过长，不执行回调

                var method = binding.value.method;

                var params = binding.value.params;

                method(params);

            }

        },false);

    }

})