jquery返回顶部和底部插件和解决ie6下fixed插件

(function($){
    //返回顶部和底部插件
    $.fn.extend({ 
        goTopBootom:function (options){
            //默认参数
            var defaults = {
                "upBtn":".up", //被点击返回顶部的按钮
                "downBtn":".down", //被点击返回底部的按钮
                "inTms":300, //此功能元素出现的时间
                "outTms":300, //此功能元素隐藏的时间
                "speed":500 //返回顶部或者底部的速度
            };
            var options = $.extend(defaults,options)
            return this.each(function(){
                var _this = $(this);
                var oHtmlBody = $('html,body');
                var oBodyH = document.body.clientHeight;
                var oUp = $(this).find(options.upBtn);
                var oDown = $(this).find(options.downBtn);
                $(this).css("top",window.screen.availHeight/2-100+"px");
                $(window).scroll(function() {        
                    if($(window).scrollTop() >= 200){
                        _this.fadeIn(options.inTms); 
                    }else{    
                        _this.fadeOut(options.inTms);    
                    }  
                });
                oUp.click(function(){oHtmlBody.animate({scrollTop: '0px'}, options.speed);});
                oDown.click(function(){oHtmlBody.animate({scrollTop: oBodyH + 'px'}, options.speed);});
            });
        },
        //解决ie6下fixed插件
        ie6fixedbug: function () {
            return this.each(function(){
                var m = (window.screen.height - $(this).height()) / 3;
                var obj = $(this);
                $(window).scroll(function () {
                    obj.css("top",(document.body.scrollTop || document.documentElement.scrollTop) + m + 'px');
                });
                $(window).resize(function () {
                    obj.css("top",(document.body.scrollTop || document.documentElement.scrollTop) + m + 'px');
                });
            });
        }
    });
}(jQuery));