$(function () {

    var isMouseDown = false;

    var currentTh = null;

   $('table th').bind({

       mousedown:function (e) {

           var $th = $(this);

           var left = $th.offset().left; //元素距左

           var rightPos = left + $th.outerWidth();

           if (rightPos-4<= e.pageX && e.pageX <= rightPos) {

               isMouseDown = true;

               currentTh = $th;

               $('table th').css('cursor','ew-resize');

               //创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止

               var bodyWidth = $('body').width();

               var bodyHeight = $('body').height();

               $('body').append('<div id="mask" style="opacity:0;top:0px;left:0px;cursor:ew-resize;background-color:green;position:absolute;z-index:9999;width:'+bodyWidth+'px;height:'+bodyHeight+'px;"></div>');

           }

       }

   });

   $('body').bind({

       mousemove:function(e) {

           //移动到column右边缘提示

           $('table th').each(function (index,eleDom) {

               var ele = $(eleDom);

               var left = ele.offset().left; //元素距左

               var rightPos = left + ele.outerWidth();

               if (rightPos-4<= e.pageX && e.pageX <= rightPos) { //移到列右边缘

                   ele.css('cursor','ew-resize');

               }else{

                   if(!isMouseDown){ //不是鼠标按下的时候取消特殊鼠标样式

                       ele.css("cursor","auto");

                   }

               }

           });

           //改变大小

           if(currentTh != null){

               if(isMouseDown){ //鼠标按下了，开始移动

                   var left = currentTh.offset().left;

                   var paddingBorderLen = currentTh.outerWidth()-currentTh.width();

                   currentTh.width((e.pageX-left-paddingBorderLen)+'px');

               }

           }

       },

       mouseup:function (e) {

           isMouseDown = false;

           currentTh = null;

           $('table th').css('cursor','auto');

           $('#mask').remove();

       }

   });

});