Affix is used to handle the positioning of components based on the scroll position of the window with top and bottom boundaries.
The ‘floating’ of the ‘top of page’ link at the bottom of the screen, is a live demo of the widget.
Positioning via CSS
The affix widget toggles between three classes, each representing a particular state:
.affix-bottom. You must provide the styles for these classes yourself (independent of this widget) to handle the actual positions.
Here’s how the affix widget works:
- To start, the widget adds
.affix-topto indicate the element is in its top-most position. At this point no CSS positioning is required.
- Scrolling past the element you want affixed should trigger the actual affixing. This is where
position: fixed;(provided by Bootstrap’s CSS).
- If a bottom offset is defined, scrolling past it should replace
.affix-bottom. Since offsets are optional, setting one requires you to set the appropriate CSS. In this case, add
Follow the above steps to set your CSS for either of the usage options below.
Via Data Attributes
To easily add affix behavior to any element, just add
data-cfw="affix" to the element you want to spy on. Use offsets to define when to toggle the pinning of an element.
data-cfw-affix-, as in
|offset||number | function | object||0||Pixels to offset from screen when calculating position of scroll. If a single number is provided, the offset will be applied in both top and bottom directions. To provide a unique, bottom and top offset just provide an object
|target||selector | node | jQuery element||the `window` object||Specifies the target element of the affix.|
Activates an element to be affixed. Accepts an optional options object.
Recalculates the state of the affix based on the dimensions, position, and scroll position of the relevant elements. The
.affix-bottom classes are added to or removed from the affixed content according to the new state. This method needs to be called whenever the dimensions of the affixed content or the target element are changed, to ensure correct positioning of the affixed content.
CFW’s affix widget exposes a few events for hooking into affix functionality.
|init.cfw.affix||This event is fired after the affix element has been initialized.|
|affix.cfw.affix||This event is immediately before after the element is affixed.|
|affixed.cfw.affix||This event is after after the element has been affixed.|
|affix-top.cfw.affix||This event is fired immediately before the element is affixed-top.|
|affixed-top.cfw.affix||This event is fired after the element has been affixed-top.|
|affix-bottom.cfw.affix||This event is immediately before after the element is affixed-bottom.|
|affixed-bottom.cfw.affix||This event is fired after the element has been affixed-bottom.|