Extract parameter value from url using regular expressions

You almost had it, just need to escape special regex chars:

regex = /http\:\/\/www\.youtube\.com\/watch\?v=([\w-]{11})/;

url = 'http://www.youtube.com/watch?v=Ahg6qcgoay4';
id = url.match(regex)[1]; // id = 'Ahg6qcgoay4'

Edit: Fix for regex by soupagain.

Why dont you take the string and split it

Example on the url

var url = "http://www.youtube.com/watch?p=DB852818BF378DAC&v=1q-k-uN73Gk"

you can do a split as

var params = url.split("?")[1].split("&");

You will get array of strings with params as name value pairs with "=" as the delimiter.

Not tested but this should work:

/\?v=([a-z0-9\-]+)\&?/i

v is a query parameter, technically you need to consider cases ala: http://www.youtube.com/watch?p=DB852818BF378DAC&v=1q-k-uN73Gk

In .NET I would recommend to use System.Web.HttpUtility.ParseQueryString

HttpUtility.ParseQueryString(url)["v"];

And you don't even need to check the key, as it will return null if the key is not in the collection.