Websocket不接收消息

服务器端：

<?php
  $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
  socket_bind($socket, '127.0.0.1', 8000);
  socket_listen($socket);
  $client = socket_accept($socket);
  $handshake = socket_read($client, 1024);
  preg_match('/Sec-WebSocket-Key': (.+?)'r'n/', $handshake, $accept);
  $accept = base64_encode(sha1("$accept[1]258EAFA5-E914-47DA-95CA-C5AB0DC85B11", true));
  $handshake = "HTTP/1.1 101 Switching Protocols'r'n";
  $handshake .= "Upgrade: websocket'r'n";
  $handshake .= "Connection: Upgrade'r'n";
  $handshake .= "Sec-WebSocket-Accept: $accept'r'n'r'n";
  socket_write($client, $handshake.chr(0), strlen($handshake.chr(0)));
  socket_write($client, 's'.chr(0));
  sleep(5);
  socket_close($client);
  socket_close($socket);
?>

客户端：

<div id="output"></div>
<script>
    if ("WebSocket" in window) {
        var socket = new WebSocket('ws://127.0.0.1:8000');
        socket.onopen = function() {
            document.getElementById('output').innerHTML += 'socket open<br />';
        }
        socket.onmessage = function(msg) {
            document.getElementById('output').innerHTML += 'new msg: '+msg.data+'<br />';
        }
        socket.onclose = function() {
            document.getElementById('output').innerHTML += 'socket close';
        }
    }
</script>

我得到"插座打开"，5秒钟后"插座关闭"。我没有收到服务器发送的"s"
已在Firefox和Chrome上试用。

我做错了什么？