XMLHttpRequest标记

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            <div class="grid--cell mb0 mt8">Closed <span title="2012-12-04 04:23:02Z" class="relativetime">7 years ago</span>.</div>
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var xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.onreadystatechange = receiveResponse;
xhr.send();

Does the "true" parameter imply that the object loads asynchronously? If this is not the case, what does the "true" do specifically?

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