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));