slideUp()如何在jQuery中工作？我正在尝试制作自己的幻灯片()

// Generate shortcuts for custom animations
jQuery.each({
    slideDown: genFx("show",1),slideUp: genFx("hide",slidetoggle: genFx("toggle",fadeIn: { opacity: "show" },fadeOut: { opacity: "hide" },fadetoggle: { opacity: "toggle" }
},function( name,props ) {
    jQuery.fn[ name ] = function( speed,easing,callback ) {
        return this.animate( props,speed,callback );
    };
});

我知道这是函数的简写,所以我逐渐介绍GenFX

function genFx( type,num ) {
    var obj = {};

    jQuery.each( fxAttrs.concat.apply([],fxAttrs.slice(0,num)),function() {
        obj[ this ] = type;
    });

    return obj;
}

然后是fxAttrs

fxAttrs = [
        // height animations
        [ "height","marginTop","marginBottom","paddingTop","paddingBottom" ],// width animations
        [ "width","marginLeft","marginRight","paddingLeft","paddingRight" ],// opacity animations
        [ "opacity" ]
    ],

但我无法弄清楚这段代码是如何工作的,或者我将如何创建影响HTML宽度属性的slideLeft或slideRight.