PROSAGA码农传奇-webrtc-WebRTC数据通道带有手动信号，请举例？

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  <P>
    这里是。单击下面的蓝色按钮
    <a href="https://stackoverflow.com/a/54985729">
      二
    </A>
     不同的标签/窗口/浏览器/机器：
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  <P>
  </p>
  <div class =“snippet”data-lang =“js”data-hide =“false”data-console =“true”data-babel =“false”>
    <div class =“snippet-code”>
       <pre class="snippet-code-js lang-js prettyprint-override">
        <code>
          const config = {iceServers: [{urls: "stun:stun.1.google.com:19302"}]};
const pc = new RTCPeerConnection(config);
const dc = pc.createDataChannel("chat", {negotiated: true, id: 0});
const log = msg => div.innerHTML += `<br>${msg}`;
dc.onopen = () => chat.select();
dc.onmessage = e => log(`> ${e.data}`);
pc.oniceconnectionstatechange = e => log(pc.iceConnectionState);

chat.onkeypress = function(e) {
  if (e.keyCode != 13) return;
  dc.send(chat.value);
  log(chat.value);
  chat.value = "";
};

async function createOffer() {
  button.disabled = true;
  await pc.setLocalDescription(await pc.createOffer());
  pc.onicecandidate = ({candidate}) => {
    if (candidate) return;
    offer.value = pc.localDescription.sdp;
    offer.select();
    answer.placeholder = "Paste answer here";
  };
}

offer.onkeypress = async function(e) {
  if (e.keyCode != 13 || pc.signalingState != "stable") return;
  button.disabled = offer.disabled = true;
  await pc.setRemoteDescription({type: "offer", sdp: offer.value});
  await pc.setLocalDescription(await pc.createAnswer());
  pc.onicecandidate = ({candidate}) => {
    if (candidate) return;
    answer.focus();
    answer.value = pc.localDescription.sdp;
    answer.select();
  };
};

answer.onkeypress = function(e) {
  if (e.keyCode != 13 || pc.signalingState != "have-local-offer") return;
  answer.disabled = true;
  pc.setRemoteDescription({type: "answer", sdp: answer.value});
};
        </code>
      </pre>
       <pre class="snippet-code-html lang-html prettyprint-override">
        <code>
          <button id="button" onclick="createOffer()">Offer:</button>
<textarea id="offer" placeholder="Paste offer here"></textarea>
Answer: <textarea id="answer"></textarea><br><div id="div"></div>
Chat: <input id="chat"><br>
        </code>
      </pre>
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  <P>
  </p>
  <P>
    然后按照下列步骤操作
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  <OL>
    <LI>
      在窗口A中，按
       <code>
        Offer
      </code>
       按钮并将要约复制到
剪贴板。
    </LI>
    <LI>
      在Window B中，将该商品粘贴到“Paste offer here”并点击ENTER键。
    </LI>
    <LI>
      复制几秒钟后出现的答案。
    </LI>
    <LI>
      返回到窗口A并将答案粘贴到“在此处粘贴答案”，然后按ENTER键。
    </LI>
  </醇>
  <P>
    您现在应该看到一条消息说您已“连接”。输入聊天框进行聊天！
  </p>
  <P>
    如果您和朋友以某种方式交换提议/答案，您现在可以直接进行点对点连接。这应该适用于全世界（模对称NAT）;没有涉及数据服务器。
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