reloadr.js

/*
TO USE: include reloadr.js and tell it what to check:

	Reloadr.go({
		client: [
			'/js/main.js',
			'/css/layout.css'
		],
		server: [
			'index.php'
		],
		path: '/reloadr.php',
		frequency: 2000
	});

	All keys are optional. If you don't give client or server, though, it won't do anything.

	Shortcut: Reloadr.watch([
		'/js/main.js',
		'/css/layout.css'
	]);
*/

var Reloadr = {
	options: {
		frequency: 2000,
		client: [],
		server: [],
		path: '/reloadr.php'
	},
	req: new XMLHttpRequest(),
	timeout: null,
	watch: function(options) { this.go.call(this, options); },
	go: function(options) {
		if ( options )

			// deal with array being passed
			if ( typeof options.length != 'undefined')
				this.options.client = options;
				
			// change any options given
			else for (x in options)
				this.options[x] = options[x];

		// set up new timeout
		clearTimeout(this.timeout);
		this.timeout = setTimeout(function() {
			Reloadr.poll.call(Reloadr);
		}, this.options.frequency);
	},
	ajax: function(url, callback) {
		this.req.open("GET", url, false);
		this.req.setRequestHeader('If-Modified-Since', window._Reloadr_LoadTime.toUTCString());
		this.req.send(null);
		if (this.req.status == 200)
			callback.call(
				Date.parse(
					this.req.getResponseHeader('Last-Modified')
				)
			);
	},
	poll: function(options) {
		var urls = this.options.client.slice();

		// build url for server-side files
		if ( this.options.server.length )
			urls.push(this.options.path +'?'+ this.options.server.join(','));

		// check 'em
		for (i in urls)
			this.ajax.call(this, urls[i], function() {
				if (this > Date.parse(window._Reloadr_LoadTime))
					location.reload();
			});

		this.go();
	},
	init: function(options) {
		window._Reloadr_LoadTime = new Date();
	}
};
Reloadr.init();