Nesting Output BuffersIf there is an output buffer active when a new buffer is started, the new buffer will be nested inside the previously active buffer. The inner buffer will behave the same way regardless whether it is nested but output buffered by it will not be buffered by the outer buffer. Only output flushed by the inner buffer will be buffered by the outer buffer.
Most Calling ob_get_level or ob_get_status will return the nesting level of the active output buffer. Caution
The value for identical levels between ob_get_level
and ob_get_status is off by one.
For ob_get_level
the first level is |