drag preventdefault的bug

by hui liu

HTML

<div class="drag" draggable="true">drag me</div>
<div class="log">
</div>

CSS

* {
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  -o-user-select: none;
  user-select: none;
}

JavaScript

$('body').on('mousedown', function(ev) {
  this.startX = ev.clientX;
  this.startY = ev.clientY;
  this.isClick = 1;
  //如果不阻止默认行为就会出现结果一直是0的情况，属于浏览器行为
  ev.preventDefault();
}).on('mousemove', function(ev) {
  var offsetX = Math.abs(ev.clientX - this.startX);
  var offsetY = Math.abs(ev.clientY - this.startY);
  if (!this.isClick) return;
  $('.log').html(offsetX + '--' + offsetY);

})