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How to split a word for getting a specific value in Javascript or Jquery? [duplicate]

How do I get the last segment of a url? I have the following script which displays the full url of the anchor tag clicked:
$(".tag_name_goes_here").live('click', function(event)
{
event.preventDefault();
alert($(this).attr("href"));
});
If the url is
http://mywebsite/folder/file
how do I only get it to display the "file" part of the url in the alert box?

You can also use the lastIndexOf() function to locate the last occurrence of the / character in your URL, then the substring() function to return the substring starting from that location:
console.log(this.href.substring(this.href.lastIndexOf('/') + 1));
That way, you'll avoid creating an array containing all your URL segments, as split() does.

var parts = 'http://mywebsite/folder/file'.split('/');
var lastSegment = parts.pop() || parts.pop(); // handle potential trailing slash
console.log(lastSegment);

window.location.pathname.split("/").pop()

The other answers may work if the path is simple, consisting only of simple path elements. But when it contains query params as well, they break.
Better use URL object for this instead to get a more robust solution. It is a parsed interpretation of the present URL:
Input:
const href = 'https://stackoverflow.com/boo?q=foo&s=bar'
const segments = new URL(href).pathname.split('/');
const last = segments.pop() || segments.pop(); // Handle potential trailing slash
console.log(last);
Output: 'boo'
This works for all common browsers. Only our dying IE doesn't support that (and won't). For IE there is a polyfills available, though (if you care at all).

Just another solution with regex.
var href = location.href;
console.log(href.match(/([^\/]*)\/*$/)[1]);

Javascript has the function split associated to string object that can help you:
const url = "http://mywebsite/folder/file";
const array = url.split('/');
const lastsegment = array[array.length-1];

Shortest way how to get URL Last Segment with split(), filter() and pop()
function getLastUrlSegment(url) {
return new URL(url).pathname.split('/').filter(Boolean).pop();
}
console.log(getLastUrlSegment(window.location.href));
console.log(getLastUrlSegment('https://x.com/boo'));
console.log(getLastUrlSegment('https://x.com/boo/'));
console.log(getLastUrlSegment('https://x.com/boo?q=foo&s=bar=aaa'));
console.log(getLastUrlSegment('https://x.com/boo?q=foo#this'));
console.log(getLastUrlSegment('https://x.com/last segment with spaces'));
Works for me.

Or you could use a regular expression:
alert(href.replace(/.*\//, ''));

var urlChunks = 'mywebsite/folder/file'.split('/');
alert(urlChunks[urlChunks.length - 1]);

Returns the last segment, regardless of trailing slashes:
var val = 'http://mywebsite/folder/file//'.split('/').filter(Boolean).pop();
console.log(val);

I know, it is too late, but for others:
I highly recommended use PURL jquery plugin. Motivation for PURL is that url can be segmented by '#' too (example: angular.js links), i.e. url could looks like
http://test.com/#/about/us/
or
http://test.com/#sky=blue&grass=green
And with PURL you can easy decide (segment/fsegment) which segment you want to get.
For "classic" last segment you could write:
var url = $.url('http://test.com/dir/index.html?key=value');
var lastSegment = url.segment().pop(); // index.html

Get the Last Segment using RegEx
str.replace(/.*\/(\w+)\/?$/, '$1');
$1 means using the capturing group. using in RegEx (\w+) create the first group then the whole string replace with the capture group.
let str = 'http://mywebsite/folder/file';
let lastSegment = str.replace(/.*\/(\w+)\/?$/, '$1');
console.log(lastSegment);

Also,
var url = $(this).attr("href");
var part = url.substring(url.lastIndexOf('/') + 1);

Building on Frédéric's answer using only javascript:
var url = document.URL
window.alert(url.substr(url.lastIndexOf('/') + 1));

If you aren't worried about generating the extra elements using the split then filter could handle the issue you mention of the trailing slash (Assuming you have browser support for filter).
url.split('/').filter(function (s) { return !!s }).pop()

window.alert(this.pathname.substr(this.pathname.lastIndexOf('/') + 1));
Use the native pathname property because it's simplest and has already been parsed and resolved by the browser. $(this).attr("href") can return values like ../.. which would not give you the correct result.
If you need to keep the search and hash (e.g. foo?bar#baz from http://quux.com/path/to/foo?bar#baz) use this:
window.alert(this.pathname.substr(this.pathname.lastIndexOf('/') + 1) + this.search + this.hash);

To get the last segment of your current window:
window.location.href.substr(window.location.href.lastIndexOf('/') +1)

you can first remove if there is / at the end and then get last part of url
let locationLastPart = window.location.pathname
if (locationLastPart.substring(locationLastPart.length-1) == "/") {
locationLastPart = locationLastPart.substring(0, locationLastPart.length-1);
}
locationLastPart = locationLastPart.substr(locationLastPart.lastIndexOf('/') + 1);

var pathname = window.location.pathname; // Returns path only
var url = window.location.href; // Returns full URL
Copied from this answer

// Store original location in loc like: http://test.com/one/ (ending slash)
var loc = location.href;
// If the last char is a slash trim it, otherwise return the original loc
loc = loc.lastIndexOf('/') == (loc.length -1) ? loc.substring(0,loc.length-1) : loc.substring(0,loc.lastIndexOf('/'));
var targetValue = loc.substring(loc.lastIndexOf('/') + 1);
targetValue = one
If your url looks like:
http://test.com/one/
or
http://test.com/one
or
http://test.com/one/index.htm
Then loc ends up looking like:
http://test.com/one
Now, since you want the last item, run the next step to load the value (targetValue) you originally wanted.
var targetValue = loc.substr(loc.lastIndexOf('/') + 1);
// Store original location in loc like: http://test.com/one/ (ending slash)
let loc = "http://test.com/one/index.htm";
console.log("starting loc value = " + loc);
// If the last char is a slash trim it, otherwise return the original loc
loc = loc.lastIndexOf('/') == (loc.length -1) ? loc.substring(0,loc.length-1) : loc.substring(0,loc.lastIndexOf('/'));
let targetValue = loc.substring(loc.lastIndexOf('/') + 1);
console.log("targetValue = " + targetValue);
console.log("loc = " + loc);

Updated raddevus answer :
var loc = window.location.href;
loc = loc.lastIndexOf('/') == loc.length - 1 ? loc.substr(0, loc.length - 1) : loc.substr(0, loc.length + 1);
var targetValue = loc.substr(loc.lastIndexOf('/') + 1);
Prints last path of url as string :
test.com/path-name = path-name
test.com/path-name/ = path-name

I am using regex and split:
var last_path = location.href.match(/./(.[\w])/)[1].split("#")[0].split("?")[0]
In the end it will ignore # ? & / ending urls, which happens a lot. Example:
https://cardsrealm.com/profile/cardsRealm -> Returns cardsRealm
https://cardsrealm.com/profile/cardsRealm#hello -> Returns cardsRealm
https://cardsrealm.com/profile/cardsRealm?hello -> Returns cardsRealm
https://cardsrealm.com/profile/cardsRealm/ -> Returns cardsRealm

I don't really know if regex is the right way to solve this issue as it can really affect efficiency of your code, but the below regex will help you fetch the last segment and it will still give you the last segment even if the URL is followed by an empty /. The regex that I came up with is:
[^\/]+[\/]?$

I know it is old but if you want to get this from an URL you could simply use:
document.location.pathname.substring(document.location.pathname.lastIndexOf('/.') + 1);
document.location.pathname gets the pathname from the current URL.
lastIndexOf get the index of the last occurrence of the following Regex, in our case is /.. The dot means any character, thus, it will not count if the / is the last character on the URL.
substring will cut the string between two indexes.

if the url is http://localhost/madukaonline/shop.php?shop=79
console.log(location.search); will bring ?shop=79
so the simplest way is to use location.search
you can lookup for more info here
and here

You can do this with simple paths (w/0) querystrings etc.
Granted probably overly complex and probably not performant, but I wanted to use reduce for the fun of it.
"/foo/bar/"
.split(path.sep)
.filter(x => x !== "")
.reduce((_, part, i, arr) => {
if (i == arr.length - 1) return part;
}, "");
Split the string on path separators.
Filter out empty string path parts (this could happen with trailing slash in path).
Reduce the array of path parts to the last one.

Adding up to the great Sebastian Barth answer.
if href is a variable that you are parsing, new URL will throw a TypeError so to be in the safe side you should try - catch
try{
const segments = new URL(href).pathname.split('/');
const last = segments.pop() || segments.pop(); // Handle potential trailing slash
console.log(last);
}catch (error){
//Uups, href wasn't a valid URL (empty string or malformed URL)
console.log('TypeError ->',error);
}

I believe it's safer to remove the tail slash('/') before doing substring. Because I got an empty string in my scenario.
window.alert((window.location.pathname).replace(/\/$/, "").substr((window.location.pathname.replace(/\/$/, "")).lastIndexOf('/') + 1));

Bestway to get URL Last Segment Remove (-) and (/) also
jQuery(document).ready(function(){
var path = window.location.pathname;
var parts = path.split('/');
var lastSegment = parts.pop() || parts.pop(); // handle potential trailing slash
lastSegment = lastSegment.replace('-',' ').replace('-',' ');
jQuery('.archive .filters').before('<div class="product_heading"><h3>Best '+lastSegment+' Deals </h3></div>');
});

A way to avoid query params
const urlString = "https://stackoverflow.com/last-segment?param=123"
const url = new URL(urlString);
url.search = '';
const lastSegment = url.pathname.split('/').pop();
console.log(lastSegment)

Regex - Regular expression pattern failing on URL GET parameter

I'm trying to do a URL GET variable replace, however the regular expression for checking whether the variable exists in amongst other GET variables is returning true when I am expecting it to return false.
The pattern I am using is: &sort=.*&
Test URL: http://localhost/search?location=any&sort=asc
Am I right to believe that this pattern should be returning false on the basis that their is no ampersand character following the sort parameter's value?
Full code:
var sort = getOptionValue($(this).attr('id'));
var url = document.URL;
if(url.indexOf('?') == -1) {
url = url+'?sort='+sort;
} else {
if(url.search('/&sort=.*&/i')) {
url.replace('/&sort=.*&/i','&sort='+sort+'&');
}
else if(url.search('/&sort=.*/i')) {
url.replace('/&sort=.*/i','&sort='+sort);
}
}

Am I right to believe that this pattern should be returning false on the basis that their is no ampersand character following the sort parameter's value?
Well, you are using String.search, which, according to the linked documentation:
If successful, search returns the index of the regular expression inside the string. Otherwise, it returns -1.
So it will return -1, or 0 or greater when there is a match. So you should test for -1, not truthiness.
Also, there is no need to pass the regexes as strings, you might as well use:
url.replace(/&sort=.*&/i,'&sort='+sort+'&');
Further, keep in mind that replace will create a new string, not replace in the string (strings in Javascript are immutable).
Finally, I don't see the need for searching for the string, and then replacing it -- it seems that you always want to replace &sort=SOMETHING with &sort=SOMETHING_ELSE, so just do that:
if(url.indexOf('?') == -1) {
url = url+'?sort='+sort;
} else {
url = url.replace(/&sort=[^&]*/i, '&sort=' + sort);
}

The javascript string function search() returns -1 if not found, not false. Your code should read:
if(url.search('/&sort=.*&/i') != -1) {
url.replace('/&sort=.*&/i','&sort='+sort+'&');
}
else if(url.search('/&sort=.*/i') != -1) {
url.replace('/&sort=.*/i','&sort='+sort);
}

You should check
if(url.search('/&sort=.*&/i') >= 0)
then it should work

You could use this code
var url = 'http://localhost/search?location=any&sort=asc';
var vars = {};
var parts = url.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value) {
vars[key] = value;
});
console.log(vars);
//vars is an object with two properties: location and sort

This can be done by using
url.replace(/([?&])(sort=)([^&?]*)/, "$1$2" + sort);
The match broken down
Group 1 matches for ? or &
Group 2 matches sort=
Group 3 matches anything that is not a & or ?
Then "$1$2" + sort will replace all 3 group matches with the first 2 + your variable
examples using string "REPLACE" instead of your sort variable
url = "http://localhost/search?location=any&sort=asc&a=z"
url.replace(/([?&])(sort=)([^&?]*)/, "$1$2" + "REPLACE");
// => "http://localhost/search?location=any&sort=REPLACE&a=z"
url = "http://localhost/search?location=any&sort=asc"
url.replace(/([?&])(sort=)([^&?]*)/, "$1$2" + "REPLACE");
// => "http://localhost/search?location=any&sort=REPLACE"
url = "http://localhost/search?sort=asc"
url.replace(/([?&])(sort=)([^&?]*)/, "$1$2" + "REPLACE");
// => "http://localhost/search?sort=REPLACE"
url = "http://localhost/search?sort=asc&z=y"
url.replace(/([?&])(sort=)([^&?]*)/, "$1$2" + "REPLACE");
// => "http://localhost/search?sort=REPLACE&z=y"

The pattern I am using is: &sort=.*& Test URL:
http://localhost/search?location=any&sort=asc
Am I right to believe that this pattern should be returning false on
the basis that their is no ampersand character following the sort
parameter's value?
you are assuming right. But in your code you have else if(url.search('/&sort=.*/i')) which will match and thus still replace the value.
You should also note that your code would turn http://localhost/search?sort=asc&location=any&some=more into http://localhost/search?sort=asc&some=more. that's because because .* is greedy (trying to match as much as possible). You can avoid that by telling it to match as little as possible by appending a ? like so .*?.
That said, I believe you may be better off with a library that knows how URLs actually work. You're not compensating for parameter position, possible escaped values etc. I suggest you have a look at URI.js and replace your wicked regex with
var uri = URI(document.URL),
data = uri.query(true);
data.foo = 'bazbaz';
uri.query(data);

Trimming a string from the end in Javascript

In Javascript, how can I trim a string by a number of characters from the end, append another string, and re-append the initially cut-off string again?
In particular, I have filename.png and want to turn it into filename-thumbnail.png.
I am looking for something along the lines of:
var sImage = "filename.png";
var sAppend = "-thumbnail";
var sThumbnail = magicHere(sImage, sAppend);

You can use .slice, which accepts negative indexes:
function insert(str, sub, pos) {
return str.slice(0, pos) + sub + str.slice(pos);
// "filename" + "-thumbnail" + ".png"
}
Usage:
insert("filename.png", "-thumbnail", -4); // insert at 4th from end

Try using a regular expression (Good documentation can be found at https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions)
I haven't tested but try something like:
var re = /(.*)\.png$/;
var str = "filename.png";
var newstr = str.replace(re, "$1-thumbnail.png");
console.log(newstr);

I would use a regular expression to find the various parts of the filename and then rearrange and add strings as needed from there.
Something like this:
var file='filename.png';
var re1='((?:[a-z][a-z0-9_]*))';
var re2='.*?';
var re3='((?:[a-z][a-z0-9_]*))';
var p = new RegExp(re1+re2+re3,["i"]);
var m = p.exec(file);
if (m != null) {
var fileName=m[1];
var fileExtension=m[2];
}
That would give you your file's name in fileName and file's extension in fileExtension. From there you could append or prepend anything you want.
var newFile = fileName + '-thumbnail' + '.' + fileExtension;

Perhaps simpler than regular expressions, you could use lastindexof (see http://www.w3schools.com/jsref/jsref_lastindexof.asp) to find the file extension (look for the period - this allows for longer file extensions like .html), then use slice as suggested by pimvdb.

You could use a regular expression and do something like this:
var sImage = "filename.png";
var sAppend = "-thumbnail$1";
var rExtension = /(\.[\w\d]+)$/;
var sThumbnail = sImage.replace(rExtension, sAppend);
rExtension is a regular expression which looks for the extension, capturing it into $1. You'll see that $1 appears inside of sAppend, which means "put the extension here".
EDIT: This solution will work with any file extension of any length. See it in action here: http://jsfiddle.net/h4Qsv/

Why does this jQuery code not work?

Why doesn't the following jQuery code work?
$(function() {
var regex = /\?fb=[0-9]+/g;
var input = window.location.href;
var scrape = input.match(regex); // returns ?fb=4
var numeral = /\?fb=/g;
scrape.replace(numeral,'');
alert(scrape); // Should alert the number?
});
Basically I have a link like this:
http://foo.com/?fb=4
How do I first locate the ?fb=4 and then retrieve the number only?

Consider using the following code instead:
$(function() {
var matches = window.location.href.match(/\?fb=([0-9]+)/i);
if (matches) {
var number = matches[1];
alert(number); // will alert 4!
}
});
Test an example of it here: http://jsfiddle.net/GLAXS/
The regular expression is only slightly modified from what you provided. The global flag was removed, as you're not going to have multiple fb='s to match (otherwise your URL will be invalid!). The case insensitive flag flag was added to match FB= as well as fb=.
The number is wrapped in curly brackets to denote a capturing group which is the magic which allows us to use match.
If match matches the regular expression we specify, it'll return the matched string in the first array element. The remaining elements contain the value of each capturing group we define.
In our running example, the string "?fb=4" is matched and so is the first value of the returned array. The only capturing group we have defined is the number matcher; which is why 4 is contained in the second element.

If you all you need is to grab the value of fb, just use capturing parenthesis:
var regex = /\?fb=([0-9]+)/g;
var input = window.location.href;
var tokens = regex.exec(input);
if (tokens) { // there's a match
alert(tokens[1]); // grab first captured token
}

So, you want to feed a querystring and then get its value based on parameters?
I had had half a mind to offer Get query string values in JavaScript.
But then I saw a small kid abusing a much respectful Stack Overflow answer.
// Revised, cooler.
function getParameterByName(name) {
var match = RegExp('[?&]' + name + '=([^&]*)')
.exec(window.location.search);
return match ?
decodeURIComponent(match[1].replace(/\+/g, ' '))
: null;
}
And while you are at it, just call the function like this.
getParameterByName("fb")

How about using the following function to read the query string parameter in JavaScript:
function getQuerystring(key, default_) {
if (default_==null)
default_="";
key = key.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
var regex = new RegExp("[\\?&]"+key+"=([^&#]*)");
var qs = regex.exec(window.location.href);
if(qs == null)
return default_;
else
return qs[1];
}
and then:
alert(getQuerystring('fb'));

If you are new to Regex, why not try Program that illustrates the ins and outs of Regular Expressions

Replacing part of a string with javascript?

Let's say I have a URL that looks something like this:
http://www.mywebsite.com/param1:set1/param2:set2/param3:set3/
I've made it a varaible in my javascript but now I want to change "param2:set2" to be "param2:set5" or whatever. How do I grab that part of the string and change it?
One thing to note is where "param2..." is in the string can change as well as the number of characters after the ":". I know I can use substring to get part of the string from the front but I'm not sure how to grab it from the end or anywhere in the middle.

How about this?
>>> var url = 'http://www.mywebsite.com/param1:set1/param2:set2/param3:set3/';
>>> url.replace(/param2:[^/]+/i, 'param2:set5');
"http://www.mywebsite.com/param1:set1/param2:set5/param3:set3/"

Use regular expressions ;)
url.replace(/param2:([\d\w])+/, 'param2:new_string')

var key = "param2";
var newKey = "paramX";
var newValue = "valueX";
var oldURL = "http://www.mywebsite.com/param1:set1/param2:set2/param3:set3/";
var newURL = oldURL.replace( new RegExp( key + ":[^/]+" ), newKey + ":" + newValue);

You can pass regular expressions to the match() and replace() functions in javascript.