how to detect drag left to right with movement constrain?

Question

I want to detect direction of drag event on the static(no movement) element. From what I have searched, they use jquery-ui draggable that the element will move.

here is my try ( I use containment to stop its movement but then I cannot detect direction of drag)

 var prevX = -1; $('div').draggable({ containment: "parent", drag: function(e) { //console.log(e.pageX); if (prevX == -1) { prevX = e.pageX; return false; } // dragged left if (prevX > e.pageX) { alert('dragged left'); } else if (prevX < e.pageX) { // dragged right alert('dragged right'); } prevX = e.pageX; } }); 

 .wrapper { width: 100px; height: 100px; } .inside { width: 100px; height: 100px; background-color: yellow; } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script> <div class="wrapper"> <div class="inside"></div> </div> 

Answer 1

使用dragstart保存开始位置XY，使用end dragend比较