使表格的标题列可左右拉伸jquery插件封装

插件名称命名为:jquery.tableresize.js，代码如下：

代码如下:
/*
Writen by mlcactus, 2014-11-24
这是我封装的一个jquery插件，能够使table的各列可以左右拉伸，从而使宽度变小或变大
用法：
单个table：$("#table_id").tableresize();   
页面所有table：$("table").tableresize();
*/
(function ($) {
    $.fn.tableresize = function () {
        var _document = $("body");
        $(this).each(function () {
            if (!$.tableresize) {
                $.tableresize = {};
            }
            var _table = $(this);
            //设定ID
            var id = _table.attr("id") || "tableresize_" + (Math.random() * 100000).toFixed(0).toString();
            var tr = _table.find("tr").first(), ths = tr.children(), _firstth = ths.first();
            //设定临时变量存放对象
            var cobjs = $.tableresize[id] = {};
            cobjs._currentObj = null, cobjs._currentLeft = null;
            ths.mousemove(function (e) {
                var _this = $(this);
                var left = _this.offset().left, top = _this.offset().top, width = _this.width(), height = _this.height(), right = left + width, bottom = top + height, clientX = e.clientX, clientY = e.clientY;
                var leftside = !_firstth.is(_this) && Math.abs(left - clientX) <= 5, rightside = Math.abs(right - clientX) <= 5;
                if (cobjs._currentLeft || clientY > top && clientY < bottom && (leftside || rightside)) {
                    _document.css("cursor", "e-resize");
                    if (!cobjs._currentLeft) {