JSDT (Javascript Development Tools) is an Eclipse project aimed at implementing the JDT APIs for Javascript. Its early demos were really impressive, but it seems to not have had any releases since 2007, without any mention of what happened to it.
Does anyone know its status?
As said in the page link you provided, it is now part of WTP (Web Tool Platform)
As such, it is still included in the WTP releases since 2007, like this message illustrates, and the list of bugs for the wtp.jsdt component seems fairly active.
However, its facet (the wrapper around installing the JSDT nature) was missing until recently.