将弹出窗口定位到单击的事件位置

Question

   我编写了一个小的jQuery插件，在触发click事件的位置打开一个弹出窗口，如果弹出窗口离开窗口以避免滚动，则将弹出窗口与窗口对齐。

   (function($){
     $.fn.showPopupAtEvt = function(options){
       var defaults = $.extend({
         /**Right popup right to the event position**/
         rightAlign:false
       },options);
      // alert(defaults.rightAlign);
          /***
      m - CSS Compatibility mode
      l - left offset of the window
      t - top offset of the window
      w - width of the window
      h - height of the window
      pW - Popup width
      pH - Popup height
      tW - Total Width(Event left offset + Popup Width)
      tH - Total Height(Event top offset + Popup Height)
      ***/
        var m,l,t,w,h,pW,pH,tW,tH;
      /*****Getting popup height and width ********/
       pW = this.outerWidth() || 0;
       pH = this.outerHeight() || 0;
      m = document.compatMode == 'CSS1Compat';
      l = window.pageXOffset || (m ? document.documentElement.scrollLeft   : document.body.scrollLeft);
      t = window.pageYOffset || (m ? document.documentElement.scrollTop    : document.body.scrollTop);
      w = window.innerWidth  || (m ? document.documentElement.clientWidth  : document.body.clientWidth);
      h = window.innerHeight || (m ? document.documentElement.clientHeight : document.body.clientHeight);
      w += l;
      h += t;
      /*****Getting event positions ****/
      mouseX = event.clientX?event.clientX:event.pageX;
      mouseY = event.clientY?event.clientY:event.pageY;
      /****** with scrolling positions*****/
      mouseX  += l;
      mouseY  += t;
      tW = mouseX + pW;
      tH = mouseY + pH;
          if(tH>h){
          diff = tH - h+17;
          mouseY -= diff;
      }
      if(!defaults.rightAlign){
        if(tW>w){
          diff = tW - w +17;
          mouseX -= diff;
        }
      }
      else{
        mouseX = mouseX - pW;
      }
      mouseX = mouseX<0?0:mouseX;
      mouseY = mouseY<0?0:mouseY;
      this.show().css({left:mouseX,top:mouseY});
/**     this.show().position({left:mouseX,top:mouseY});
      console.log(this.parent().css('position'));**/
     };
  }(jQuery));

除了一种情况外，它适用于所有地方。

如果源元素的父position is relative.无法正常工作 我知道，由于position:relative样式，目标弹出窗口未正确对齐，但我不知道如何解决问题。
有人能帮帮我吗..... 这是jsfiddle