javascript - 使用 $.get 定期轮询 Express 服务器

Question

有一个带有服务器时间生成器的 Express 服务器。生成的时间发送到客户端页面gtm.hbs 。如何从客户端页面定期轮询服务器？我正在寻找 ajax 解决方案。

这是存储在 \routes\getTime.js 中的服务器端代码:

module.exports = {  
    sendCurrentUTCTimeString: function(req, res, next) {
        var currentUTCTime = new Date();
        var currentUTCHours = currentUTCTime.getUTCHours();
        var currentUTCMinutes = currentUTCTime.getUTCMinutes();
        var currentUTCSeconds = currentUTCTime.getUTCSeconds();

        currentUTCHours = ( currentUTCHours < 10 ? "0" : "" ) + currentUTCHours;
        currentUTCMinutes = ( currentUTCMinutes < 10 ? "0" : "" ) + currentUTCMinutes;
        currentUTCSeconds = ( currentUTCSeconds < 10 ? "0" : "" ) + currentUTCSeconds;
        currentUTCHours = ( currentUTCHours == 24 ) ? "00" : currentUTCHours;

        function pad(number, length) {
            var str = "" + number;
            while (str.length < length) {
                str = '0' + str;
            }
            return str;
        }

        var offset = new Date().getTimezoneOffset();
        offset = ((offset < 0 ? '+' : '-') + pad(parseInt(Math.abs(offset / 60)), 2) + pad(Math.abs(offset % 60), 2));
        offset = offset.match(/[\+-][0-9][0-9]/)[0];
        res.send({currentUTCTime: currentUTCTime, currentUTCHours: currentUTCHours, currentUTCMinutes: currentUTCMinutes, currentUTCSeconds:currentUTCSeconds, offset: offset});
    }
}

gettime.hbs页面代码为

<script>
    $(document).ready(function() {
        setInterval(function() {
            var currentUTCHours;
            var currentUTCMinutes;
            var currentUTCSeconds;
            var offset;
            $.get('/gettime', function(data) {
                debugger;
                console.log(data);
                currentUTCHours = data.currentUTCHours;
                currentUTCMinutes = data.currentUTCSeconds;
                currentUTCSeconds = data.currentUTCMinutes;
                offset = data.offset;
                $('#currentUTCHours').text(currentUTCHours);
                $('#currentUTCMinutes').text(currentUTCMinutes);
                $('#currentUTCSeconds').text(currentUTCSeconds);
                $('#offset').text(offset);
            });

            console.log('currentUTCHours: ' + currentUTCHours);
        }, 1500);
    });
</script>

currentUTCHours: <span id="currentUTCHours"></span><br>
currentUTCMinutes: <span id="currentUTCMinutes"></span><br>
currentUTCSeconds: <span id="currentUTCSeconds"></span><br>
offset: <span id="offset"></span><br>

在这里，我想渲染一个页面，该页面将轮询服务器，然后填充四个 <span> s 与服务器响应值。

连接服务器和客户端的路由是

app.get('/gettime', getTime.sendCurrentUTCTimeString);
app.get('/gtm', function(req, res, next) {
    res.render('gettime', {});
}); 

Answer 1

$('#currentUTCHours').text(currentUTCHours);
$('#currentUTCSeconds').text(currentUTCSeconds);

应位于 $.get() 内以使更改可见。