javascript - What does "XMLHttpRequest.timeout cannot be set for synchronous http(s) requests made from the window context" mean? -

i'm getting timeouts on synchronous xml http request in safari on mac. workaround, tried adding timeout so:

    req.open(this.method, fullurl, this.isasync);     req.setrequestheader('content-type', 'application/x-www-form-urlencoded');      var params = this.envelopeform();     req.setrequestheader("content-length", params.length);     req.timeout = 60000;  //get timeut cannot set here     req.send(params);  //without above, timeout here in safari 

with .timeout = 60000 i'm getting timeout on .send.

with .timeout=60000, i'm getting "xmlhttprequest.timeout cannot set synchronous http(s) requests made window context."

i'm not clear on "xmlhttprequest.timeout cannot set synchronous http(s) requests made window context" means. found in mozilla's documentation phrased so:

note: may not use timeout synchronous requests owning window.

is there work-around this? on msdn site found following statement regarding internet explorer:

if set xmlhttprequest time-out value larger network stack's time-out value, network stack time out first , ontimeout event not raised

-eric

timeout synchronous ajax requests can used web workers