Parsing a Vimeo ID using JavaScript?

If you want to check for Vimeo URL first:

function getVimeoId( url ) {

  // Look for a string with 'vimeo', then whatever, then a
  // forward slash and a group of digits.
  var match = /vimeo.*\/(\d+)/i.exec( url );

  // If the match isn't null (i.e. it matched)
  if ( match ) {
    // The grouped/matched digits from the regex
    return match[1];
  }
}

E.g.

getVimeoId('http://vimeo.com/11918221');

returns

11918221

regExp = /^.*(vimeo\.com\/)((channels\/[A-z]+\/)|(groups\/[A-z]+\/videos\/))?([0-9]+)/
parseUrl = regExp.exec url
return parseUrl[5]

This works for all valid Vimeo URLs which follows these patterns:

http://vimeo.com/*

http://vimeo.com/channels/*/*

http://vimeo.com/groups/*/videos/*

As URLs for Vimeo videos are made up by http://vimeo.com/ followed by the numeric id, you could do the following

var url = "http://www.vimeo.com/7058755";
var regExp = /http:\/\/(www\.)?vimeo.com\/(\d+)($|\/)/;

var match = url.match(regExp);

if (match){
    alert("id: " + match[2]);
}
else{
    alert("not a vimeo url");
}