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我从这篇文章中找到的代码开始：http ://www.bennadel.com/blog/2171-Realtime-Messaging-And-Synchronization-With-NowJS-And-Node-js.htm 。

我尝试重构 html，以便该示例使用 jQuery UI Draggable。代码粘贴在下面；服务器端不变。它工作正常，但拖动时存在闪烁问题。我认为这是一个 jQuery 问题，尽管我在想服务器端的过滤可能有问题？

另外，我想知道如何创建一个“initialPosition”函数，以便打开一个新页面会将可拖动的 div 放在正确的位置。我认为这是需要在服务器端完成的事情，理想情况下它将来自在拖动结束后写入的数据库值。

此外，除此之外，我想知道如果页面上有多个可拖动项目，代码会是什么样子。

HTML

<!DOCTYPE html>
<html>
<head>
    <title>NowJS Draggable using jQuery UI</title>
    <style type="text/css">
        html, body { height: 100%; width: 100%; overflow: hidden; }
        #draggable { width: 150px; height: 150px; border: 1px solid black; }
    </style>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"/></script>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.16/jquery-ui.min.js"/></script>
    <script type="text/javascript" src="/nowjs/now.js"></script>
    <script>
        $(function() {
            $( "#draggable" ).draggable();          
            $( "#draggable" ).bind( "drag", function( event ) {
                var newPosition = {
                    left: ( event.pageX ),
                    top: ( event.pageY ),
                };
                now.syncPosition( newPosition );
            });
            now.updatePosition = function( newPosition ){
                $( "#draggable" ).css( newPosition );
            };
        });
    </script>
</head>
<body>
    <div id="draggable"></div> 
</body>
</html>

NODE.JS（删除注释）

var sys = require( "sys" );
var http = require( "http" );
var url = require( "url" );
var path = require( "path" );
var fileSystem = require( "fs" );

var server = http.createServer(
    function( request, response ){
        fileSystem.readFile(
            __dirname+'/index.html',
            "binary",
            function( error, fileBinary ){
                if (error){
                    response.writeHead( 404 );
                    response.end();
                    return;
                }
                response.writeHead( 200 );
                response.write( fileBinary, "binary" );
                response.end();
            }
        );
    }
);

server.listen( 8080 );

(function(){
    var nowjs = require( "now" );
    var everyone = nowjs.initialize( server );
    var primaryKey = 0;
    everyone.connected(
        function(){
            this.now.uuid = ++primaryKey;
        }
    );
    everyone.now.syncPosition = function( position ){
        everyone.now.filterUpdateBroadcast( this.now.uuid, position );
    };
    everyone.now.filterUpdateBroadcast = function( masterUUID, position ){
        if (this.now.uuid == masterUUID){
            return;
        }
        everyone.now.updatePosition( position );
    };
})();

sys.puts( "Server is running on 8080" );
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