jquery效果总结

1. 隐藏和显示
   hide(speed,callback)
   show(speed,callback)
   toggle(speed,callback)

2. 淡入淡出
   fadeOut( [duration ], [ complete ] )
   fadeIn( [duration ], [ complete ] )
   fadeToggle()
   fadeTo( duration, opacity ,callback)

3. 上卷下拉
   slideDown( [duration ] [, complete ] )
   slideUp( [duration ] [, complete ] )
   slideToggle( [duration ] [, complete ] )