Callbacks

Callbacks are functions _called back_ by other functions in proper moment (eg on Ajax request error).

In *JavaScript* this pattern can be very flexible due to Closures support, which can be inline (no code break) and inherits scope (no need to passing params).

• PHP* has simple support for callback and here case is more complicated. That's why *ParamStructures* has been introduced in phpQuery. ParamStructures are just list of params, that can be your's or defined places for callback's ones. Example:

Example above shows how to easily pass custom params to callback using *ParamStructures*. For today this type of callbacks are supported by following functions:

 * `phpQuery::each()`
 * `phpQuery::map()`
 * `pq()->each()`
 * `pq()->each()`

There's also easy way to including scope, which means just variables accessible in specified point of code. It's achieved using compact() and extract() functions. Look at this modified example:

In the future this functionality will be developed.