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Update uri hash javascript

I find it hard to believe this hasn't been asked but I can find no references anywhere. I need to add a URI hash fragment and update the value if it already is in the hash. I can currently get it to add the hash but my regex doesn't appear to catch if it exists so it adds another instead of updating.
setQueryString : function() {
var value = currentPage;
var uri = window.location.hash;
var key = "page";
var re = new RegExp("([#&])" + key + "=.*#(&|$)", "i");
var separator = uri.indexOf('#') !== -1 ? "&" : "#";
if (uri.match(re)) {
return uri.replace(re, '$1' + key + "=" + value + '$2');
}
else {
return uri + separator + key + "=" + value;
}
},
Also if this can be made any cleaner while preserving other url values/hashes that would be great.
example input as requested
Starting uri value:
www.example.com#page=1 (or no #page at all)
then on click of "next page" setQueryString gets called so the values would equal:
var value = 2;
var uri = '#page1'
var key = 'page'
So the hopeful output would be '#page2'.

As to your regex question, testing if the pattern #page=(number) or &page=(number) is present combined with capturing the number, can be done with the regex /[#&]page\=(\d*)/ and the .match(regex) method. Note that = needs escaping in regexes.
If the pattern exists in the string, result will contain an array with the integer (as a string) at result[1]. If the pattern does not exist, result will be null.
//match #page=(integer) or &page=(integer)
var test = "#foo=bar&page=1";
var regex = /[#&]page\=(\d*)/;
var result = test.match(regex);
console.log(result);
If you want to dynamically set the key= to something other than "page", you could build the regex dynamically, like the following (note that backslashes needs escaping in strings, making the code a bit more convoluted):
//dynamically created regex
var test = "#foo=bar&page=1";
var key = "page"
var regex = new RegExp("[#&]" + key + "\\=(\\d*)");
var result = test.match(regex);
console.log(result);

Javascript get integer value of url parameter to replace it in function

I have some difficulties with javascript. I'm currently working out a pagination skipper.
function skip(s)
{
var url = window.location.toString();
if(location.href.match(/(\?|&)currentpage=x($|&|=)/))
{
url=url.replace('currentpage=x','currentpage='+s);
window.location=url;
}
else
{
var newUrl = url+"&currentpage="+s;
window.location=newUrl;
}
}
I would like x to match any integer, so the entire string will be replaced.
Thanks!

The regex you're looking is this:
/((\?|&)currentpage=)\d+/
It matches and captures ?|&currentpage=, and matches the number that follows, but does not capture them. You can then replace the entire match with a string of your choice:
var newUrl = location.href.replace(/([?&]currentpage=)\d+/, '$1'+s);
Assuming that s here is the value for currentpage you want to replace the x in your example with. I've replaced the (\?|&) with a character class: [?&]. It simply matches a single character that is either a ? or an &. In the replacement string I back-reference the matched group ([?&]currentpage=), using $1, and concatenate s to it. It's as simple as that. To redirect:
location.href = location.href.replace(
/([?&]currentpage=)\d+/,
'$1' + s
);
And you're home free. Try it out in your console, like so:
'http://www.example.com/page?param1=value1&currentpage=123&param2=foobar'.replace(
/([?&]currentpage=)\d+/,
'$1124'//replaced + s with 124
);
//output:
//"http://www.example.com/page?param1=value1&currentpage=124&param2=foobar"

You can use following code,
function addParameter(url, param, value) {
// Using a positive lookahead (?=\=) to find the
// given parameter, preceded by a ? or &, and followed
// by a = with a value after than (using a non-greedy selector)
// and then followed by a & or the end of the string
var val = new RegExp('(\\?|\\&)' + param + '=.*?(?=(&|$))', 'i'),
qstring = /\?.+$/;
// Check if the parameter exists
if (val.test(url)) {
// if it does, replace it, using the captured group
// to determine & or ? at the beginning
return url.replace(val, '$1' + param + '=' + value);
}
else if (qstring.test(url)) {
// otherwise, if there is a query string at all
// add the param to the end of it
return url + '&' + param + '=' + value;
}
else {
// if there's no query string, add one
return url + '?' + param + '=' + value;
}
}
Usage,
function skip(s) {
window.location = addParameter(location.href, "currentpage", s);
}
Demo

Deal with query strings in JS, like http_build_query, etc

Here's what I have
if(condition1) {
location.href = location.href+'/?site_type=normal';
}
else if(condition2) {
location.href = location.href+'/?site_type=other';
}
Of course, if the location.href already has query vars on it, thats a problem, etc.
I need to
Find the vars from the query string
if site_type already exists, replace the value with either 'normal' or 'other'
rebuild the url with the new site_type
edit:
I found I needed to account for all kinds of URLs:
domain.com
domain.com/path/to/sth/
domain.com/?site_type=normal
domain.com?var=123&foo=987
domain.com/path/?site_type=normal&var=123&foo=987
So, here's what I came up with, suggestions welcome:
var searchstring = window.location.search;
var url = window.location.href;
console.log('search: ' + searchstring);
console.log( 'url: ' + url);
// strip search from url
url = url.replace(searchstring,"");
console.log( 'url: ' + url);
//strip site_type from search
searchstring = searchstring.replace("&site_type=normal","")
.replace("&site_type=other","")
.replace("?site_type=normal","")
.replace("?site_type=other","")
.replace("?","")
;
console.log('search: ' + searchstring);
if(searchstring != ''){searchstring = '&' + searchstring;}
var final = url + '?site_type=normal' + searchstring;
final = final.replace("&&","&");
console.log('final: ' + final);

You can directly access the query string with window.location.search. You can convert it to an object using this regex trick found here.
var queryString = {};
window.location.search.replace(/([^?=&]+)(=([^&]*))?/g, function($0, $1, $2, $3) {
queryString[$1] = $3; }
);
Then set the site_type on queryString appropriately.
queryString["site_type"] = "normal";
And finally, convert it back into a string and set that as the window.location.search.
var searchString = "";
for ( q in queryString ) {
searchString+="&" + q + "=" + queryString[q];
}
window.location.search = searchString;

Here's a way to do this:
//remove existing param and append new one..
var newHref = window.location.href.replace(window.location.search,"") + '?site_type=other';
//change href
window.location.href = newHref;
works only if you have one parameter that you want to replace, otherwise it would remove all parameters.

for example if you have
yourpage.com/?site_type=normal
and you need only website not query vars you cans clear them
var novars= location.href.replace(window.location.search,"")
this case novars = youroage.com
for just getting variables u can do this:
var site_type = window.location.search.replace("?site_type=","");
here i will get site_type value whether its normal or other
this case your variable site_type = "normal"
for rebuilding url u can just add new site_type
location.href = novars+"?site_type=normal"
or
location.href = novars+"?site_type=other"

Removing a string in javascript

I have a URL say
dummy URL
http://www.google.com/?v=as12&&src=test&img=test
Now I want to remove the &src=test& part alone.I know we can use indexof but somehow I could not get the idea of getting the next ampersand(&) and removing that part alone.
Any help.The new URL should look like
http://www.google.com/?v=as12&img=test

What about using this?:
http://jsfiddle.net/RMaNd/8/
var mystring = "http://www.google.com/?v=as12&&src=test&img=test";
mystring = mystring.replace(/&src=.+&/, ""); // Didn't realize it isn't necessary to escape "&"
alert(mystring);
This assumes that "any" character will come after the "=" and before the next "&", but you can always change the . to a character set if you know what it could be - using [ ]
This also assumes that there will be at least 1 character after the "=" but before the "&" - because of the +. But you can change that to * if you think the string could be "src=&img=test"
UPDATE:
Using split might be the correct choice for this problem, but only if the position of src=whatever is still after "&&" but unknown...for example, if it were "&&img=test&src=test". So as long as the "&&" is always there to separate the static part from the part you want to update, you can use something like this:
http://jsfiddle.net/Y7LdG/
var mystring1 = "http://www.google.com/?v=as12&&src=test&img=test";
var mystring2 = "http://www.google.com/?v=as12&&img=test&src=test";
var final1 = removeSrcPair(mystring1);
alert(final1);
var final2 = removeSrcPair(mystring2);
alert(final2);
function replaceSrc(str) {
return str.replace(/src=.*/g, "");
}
function removeSrcPair(orig) {
var the_split = orig.split("&&");
var split_second = the_split[1].split("&");
for (var i = split_second.length-1; i >= 0; i--) {
split_second[i] = replaceSrc(split_second[i]);
if (split_second[i] === "") {
split_second.splice(i, 1);
}
}
var joined = split_second.join("&");
return the_split[0] + "&" + joined;
}
This still assumes a few things - the main split is "&&"...the key is "src", then comes "=", then 0 or more characters...and of course, the key/value pairs are separated by "&". If your problem isn't this broad, then my first answer seems fine. If "src=test" won't always come first after "&&", you'd need to use a more "complex" Regex or this split method.

Something like:
url = "http://www.google.com/?v=as12&&src=test&img=test"
firstPart = url.split('&&')[0];
lastPart = url.split('&&')[1];
lastPart = lastPart.split('&')[1];
newUrl = firstPart+'&'+lastPart;
document.write(newUrl);

Details: Use the split method.
Solution Edited: I changed the below to test that the last query string exists
var url = "http://www.google.com/?v=as12&&src=test&img=test";
var newUrl;
var splitString = url.split('&');
if (splitString.length > 3)
{
newURL = splitString[0] + "&" + splitString[3];
}
else
{
newURL = splitString[0];
}

Remove a query argument from a URL in javascript

I'm trying to write a function that will remove a query argument from a url in javascript. I think I have it using regex, but I'm not sure if I've missed anything. Also, I can't shake the feeling that there was probably a better way to do this that didn't involve me messing around with regex half the day and running the risk of later finding out that I didn't take some kind of corner case into account.
remove_query_argument = function(url, arg){
var query_arg_regex;
// Remove occurences that come after '&' symbols and not the first one after the '?'
query_arg_regex = new RegExp('&' + arg + '=[^(?:&|$)]*', 'ig');
url = url.replace(query_arg_regex, '');
// remove the instance that the argument to remove is the first one
query_arg_regex = new RegExp('[?]' + arg + '[^(?:&|$)]*(&?)', 'i');
url = url.replace(query_arg_regex, function (match, capture) {
if( capture != '&' ){
return '';
}else{
return '?'
}
});
return url;
}
Does anyone see any problems with this code or would like to suggest a better implementation or way of going about this?
Thanks!

If you have a lot of URL-related operations, you better try this awesome js library https://github.com/medialize/URI.js

Given a percent-encoded URL, the following function will remove field-value pairs from its query string:
var removeQueryFields = function (url) {
var fields = [].slice.call(arguments, 1).join('|'),
parts = url.split( new RegExp('[&?](' + fields + ')=[^&]*') ),
length = parts.length - 1;
return parts[0] + '?' + (length ? parts[length].slice(1) : '');
}
Some examples:
var string = 'http://server/path/program?f1=v1&f2=v2';
removeQueryFields( string, 'f1' ); // 'http://server/path/program?f2=v2'
removeQueryFields( string, 'f2' ); // 'http://server/path/program?f1=v1'
removeQueryFields( string, 'f1', 'f2' ); // 'http://server/path/program'