jQuery实现的简单拖拽功能示例

本文实例讲述了jQuery实现的简单拖拽功能。分享给大家供大家参考，具体如下：

<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>拖拽</title>
<style>
*{
  padding: 0;
  margin: 0;
}
div{
  width: 100px;
  height: 100px;
  background: #f00;
  cursor: pointer;
  position: absolute;
  left: 0;
  top: 0;
}
</style>
</head>
<body>
<div></div>
<script src="jquery.js"></script>
<script>
$(function(){
  //移动窗口的步骤
  //1、按下鼠标左键
  //2、移动鼠标
  $('div').mousedown(function(e){
    // e.pageX
    var positionDiv = $(this).offset();
    var distenceX = e.pageX - positionDiv.left;
    var distenceY = e.pageY - positionDiv.top;
    //alert(distenceX)
    // alert(positionDiv.left);
    $(document).mousemove(function(e){
      var x = e.pageX - distenceX;
      var y = e.pageY - distenceY;
      if(x<0){
        x=0;
      }else if(x>$(document).width()-$('div').outerWidth(true)){
        x = $(document).width()-$('div').outerWidth(true);
      }
      if(y<0){
        y=0;
      }else if(y>$(document).height()-$('div').outerHeight(true)){
        y = $(document).height()-$('div').outerHeight(true);
      }
      $('div').css({
        'left':x+'px',
        'top':y+'px'
      });
    });
    $(document).mouseup(function(){
      $(document).off('mousemove');
    });
  });
});
</script>
</body>
</html>

效果图如下：