jQuery Tutorial plus Question:

jQuery's ready is an event which gets triggered automatically when DOM is ready while holdReady is a signal/flag to hold this triggering. holdReady was included in 1.6 version and it works only if used before the execution/triggering of ready event. Once ready event is fired, it has nothing to do. It is useful in dynamically loading scripts before the ready starts. It release ready event execution when used with a true parameter.