normalize_url.js

function normalizeUrl(url) {
	var protocol;
	url = encodeURI(url);
	protocol = url.match(/^https?/);
	url = url.replace(/\/$/, '');
	url = url.replace(/^https?:\/\//, '');
	url = url.replace(/^www./, '');
	url = (protocol ? protocol[0] : 'http') + '://www.' + url;
	return url;
}

var http = [
	'http://vimeo.com/65980230',
	'http://www.vimeo.com/65980230',
	'http://vimeo.com/65980230/',
	'http://www.vimeo.com/65980230/',
	'www.vimeo.com/65980230',
	'www.vimeo.com/65980230/'
];

var https = [
	'https://vimeo.com/65980230',
	'https://www.vimeo.com/65980230',
	'https://vimeo.com/65980230/',
	'https://www.vimeo.com/65980230/'
]

http.forEach(function (url) {
	console.assert(normalizeUrl(url) === 'http://www.vimeo.com/65980230', 'Failed with', url);
});
https.forEach(function (url) {
	console.assert(normalizeUrl(url) === 'https://www.vimeo.com/65980230', 'Failed with', url);
});