代码示例：（标识：event_onmessage_sse_listener）
<!DOCTYPE html>
<html>
<body>
<h1 id="myH1"></h1>
<div id="myDIV"></div>
<p><b>注释：</b>Internet Explorer 不支持 Server-Sent 事件。</p>
<script>
if(typeof(EventSource) !== "undefined") {
var source = new EventSource("/html/demo_sse.php");
source.addEventListener("open", function() {
document.getElementById("myH1").innerHTML = "Getting server updates";
});
source.addEventListener("message", function(event) {
document.getElementById("myDIV").innerHTML += event.data + "<br>";
});
} else {
document.getElementById("myDIV").innerHTML = "Sorry, your browser does not support server-sent events...";
}
</script>
</body>
</html>
