> I used sync because I need to wait response from server, otherwise > "for" will run all iteration without waiting request to finish...
That is incorrect, or at least poorly stated. I feel you're standing firm on certain architectural decisions without really understanding the technologies. By default, independent async XHRs will always start and finish, calling your callbacks for important events, most commonly on overall success/failure but also firing as data is received. Yes, they will not "wait to finish" in the sense that they will not make *other* unrelated tasks wait for them to finish -- and that is A Good Thing. A few things mitigate async XHRs' ability to finish, but they will still appear to start immediately (ceding control back to the calling code block, again the Good Thing). One mitigator is the availability of client outbound connections; even fully independent XHRs are limited by the maximum number of simultaneous connections to the same domain, so connections over the max will have to wait to open. Another mitigator is whether you attempt to use the same XHR object or create + open a new, independent object; if you use the same XHR, it can only be making one outbound connection at a time. By default, MooTools will ignore attempts to reuse an XHR while it is currently running, the assumption being that you will be requesting a specific result set definition per object... while a later connection would give fresher result data, usually you want to have calls complete instead of constantly preempting each other and possibly never giving you complete results. Optionally, you can switch to use link:chain to chain one XHR's connections one after another, so what you get is a synchronous chain of asynchronous calls, very handy for "pulsed" handling, with the result set definition periodically changing. Getting to the meat of what you're describing -- and suspending for now my and others' critique of your decision to mandate two remote connections (client-to-server and server-to-server, both ill-advised) for every single client request for an RSS2JSON feed -- you want to have 600 client connections and display data as it comes in from each URL. It's absolutely clear that you need to use async calls. Probably a mixture of new XHRs every <n> iterations and link:chain in-between is the simplest right way. Advanced possibility is using Cometised conns (beyond the scope of this e-mail) if you right your assumptions about the server dumbly feeding one URL per request. Either way, you certainly haven't justified sync XHR, and I doubt you can. :P -- S.
