---
title: NetworkInformation.rtt
slug: Web/API/NetworkInformation/rtt
translation_of: Web/API/NetworkInformation/rtt
---
<p>{{apiref("Network Information API")}}{{SeeCompatTable}}</p>

<p><strong>NetworkInformation.rtt </strong>是一个只读属性，返回了当前连接下评估的往返时延（RTT, round-trip time ），并保留该值为25千分秒的最接近的整数倍。该值基于最近使用中被监测的最近保持活跃连接的应用层上的RTT测量值。它排除了到私有地址空间的连接。如果没有最近的测量数据，该值就基于底层连接技术的属性。</p>

<p>{{AvailableInWorkers}}</p>

<h2 id="Syntax">Syntax</h2>

<pre class="syntaxbox"><em>rtt</em> = NetworkInformation.rtt</pre>

<h3 id="Return_value">Return value</h3>

<p>一个数字。</p>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('Network Information', '#dom-networkinformation-rtt', 'rtt')}}</td>
   <td>{{Spec2('Network Information')}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome(61)}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatOpera(48)}}</td>
   <td>{{CompatNo}}</td>
  </tr>
  <tr>
   <td>Available in workers</td>
   <td>{{CompatChrome(61)}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatOpera(48)}}</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android Webview</th>
   <th>Chrome for Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome(50)}}</td>
   <td>{{CompatChrome(38)}}</td>
   <td>{{CompatGeckoMobile("31")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatOperaMobile(37)}}</td>
   <td>{{CompatNo}}</td>
  </tr>
  <tr>
   <td>Available in workers</td>
   <td>{{CompatChrome(50)}}</td>
   <td>{{CompatChrome(38)}}</td>
   <td>{{CompatGeckoMobile("53")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatOperaMobile(37)}}</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>