How to extract end of URL in Javascript?

Question

I have URLs in the form:

serverName/app/image/thumbnail/2012/4/23/1335228884300/bb65efd50ade4b3591dcf7f4c693042b

Where serverName is the domain name of the server.

I would like to write a JS function that accepts one of these URLs and returns the very last (right-most) forward-slash-delimited string. So if the URL above was passed into the function, it would return "bb65efd50ade4b3591dcf7f4c693042b";.

function getImageDirectoryByFullURL(url) {
    // ... Not sure how to define regexp to delimit on forward slashes,
    // or how to start searching from end of string.
}

Answer 1

split by slashes /, pop off the last and return it

function getImageDirectoryByFullURL(url){
    return url.split('/').pop()
}

//a step by step breakdown
function getImageDirectoryByFullURL(url){
    url = url.split('/'); //url = ["serverName","app",...,"bb65efd50ade4b3591dcf7f4c693042b"]
    url = url.pop();      //url = "bb65efd50ade4b3591dcf7f4c693042b"
    return url;           //return "bb65efd50ade4b3591dcf7f4c693042b"
}

what this does is split the url per / and returns an array of values in between, but not including, the slashes. then, since what's returned by split() is an array, we can use pop() to pop off the last item and return it.

Answer 2

In this case, substr() might be faster than split(). Not 100% sure.

function getImageDirectoryByFullURL(url){
    return url.substr(url.lastIndexOf("/")+1);
}

---

Edit: I forgot, you don't need to include the extra length parameter. Without passing that in you just get a substr to the end of the string, which is what is desired. While this solution is admittedly a little uglier than Joseph's answer, it is twice as fast in Chrome and something like fives times as fast in Firefox.