问使用jQuery查找相关元素

EN

var $closestRelativeParent = $elem.parents().filter(function() { 
  // reduce to only relative position or "body" elements
  var $this = $(this);
  return $this.is('body') || $this.css('position') == 'relative';
}).slice(0,1); // grab only the "first"

// Given a target, find it's first offset parent, and work out the targets position
// relative to the parent, by deducting their respective .offset() values
var $target = $("#bar"),
    $offsetParent = $target.offsetParent(),
    oTarget = $target.offset(),
    oParent = $offsetParent.offset(),
    posTop = oTarget.top - oParent.top,
    posLeft = oTarget.left - oParent.left;

// Validate this works by cloning #bar and positioning the clone directly on top
// Result should be a blue "bar" rather than a "red" one.
$target.clone().appendTo($offsetParent).attr("id", "confirm").css({
    top: posTop,
    left: posLeft
});