$.wait(group, triggerFunction ,callback)

Description: Wait to continue invocation depending on the result value of the callback function in a named thread group.

group – string, optional
a name of the thread group that this waiting should be assigned to.
Defaults to the empty string ''.
triggerFunction – function()
a method that is called to determine the trigger to wait for. The return value is evaluated according to its type. See other versions of .wait() for possible return values.
callback – function(), optional
a method that is called once before continuing.

The static $.unwait() allows to break wait states defined this way.