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I need to run a function if the URL has a specific string that can also come up as part of another string using jQuery or Javascript

I need to write a function to perform an action only if the URL has a specific string. The issue that I am finding is that the string can come up in multiple instances as part of another string. I need the function to run when the string is ONLY "?page=1". What I am finding is that the function is also being run when the string contains a string like "?page=10" , "?page=11" , "?page=12" , etc... I only need it to be done if the string is "?page=1" - that's it. How do I do that? I've tried a couple of different ways, but it does not work. Any help is appreciated. Here is the latest code that I have used that is close...but no cigar.
var location = window.location.href;
if (location.indexOf("?page=1") > -1){
//Do something
};

?page is a GET parameter. It doesn't necessarily have to be first in the URL string. I suggest you properly decode the GET params and then base your logic on that. Here's how you can do that:
function unparam(qs) {
var params = {},
e,
a = /\+/g,
r = /([^&=]+)=?([^&]*)/g,
d = function (s) { return decodeURIComponent(s.replace(a, " ")); };
while (e = r.exec(qs)) {
params[d(e[1])] = d(e[2]);
}
return params;
}
var urlParams = unparam(window.location.search.substring(1));
if(urlParams['page'] == '1') {
// code here
}
Alternatively, a regex with word boundaries would have worked:
if(/\bpage=1\b/.test(window.location.search)) {
// code here
}

if(location .indexOf("?page=1&") != -1 || (location .indexOf("?page=1") + 7 == i.length) ) {
}

You could look at the character immediately following the string "?page=1" in the url. If it's a digit,you don't have a match otherwise you do. You could trivially do something like this:
var index = location.indexOf("?page=1"); //Returns the index of the string
var number = location.charCodeAt(index+x); //x depends on the search string,here x = 7
//Unicode values for 0-9 is 48-57, check if number lies within this range
Now that you have the Unicode value of the next character, you can easily deduce if the url contains the string you require or not. I hope this points you in the right direction.

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);

Validation of URL without www in JavaScript

Can anyone tell the regular expression for URL validation in JavaScript?
I need to validate for http/https://example.com/...
I tried using
((^http/://[a-zA-Z][0-9a-zA-Z+\\-\\.]*:)?/{0,2}[0-9a-zA-Z;/?:#&=+$\\.\\-_!~*'()%]+)?(#[0-9a-zA-Z;/?:#&=+$\\.\\-_!~*'()%]+)?
The examples that i tried to check were:
http://google.com
https://google.com
www.google.com

You could try something like this:
var url = "Some url...";
var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*#)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%#!\-\/]))?/
if (regexp.test(url)) {
alert("Match");
} else {
alert("No match");
}

Try:
function isUrl(s) {
var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*#)?(\S+)\
(:[0-9]+)?(\/|\/([\w#!:.?+=&%#!\-\/]))?/
return regexp.test(s);
}
if (isUrl("your_url_here")) {
console.log("URL is valid");
} else {
console.log("URL is invalid");
}
via: http://snippets.dzone.com/posts/show/452

A much more simplified version could be: ^http\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,6}(/\S*)?$
I don't know if this is sufficient for you though, as I don't know what you want to do with the results.

Maybe you could just:
s,(https?://)(?!www\.),\1www.,
and use jquery to validate the transformed string?
It would avoid the job of writing yet another regex to match an URL...

How to know if JavaScript string.replace() did anything?

The replace function returns the new string with the replaces, but if there weren't any words to replace, then the original string is returned. Is there a way to know whether it actually replaced anything apart from comparing the result with the original string?

A simple option is to check for matches before you replace:
var regex = /i/g;
var newStr = str;
var replaced = str.search(regex) >= 0;
if(replaced){
newStr = newStr.replace(regex, '!');
}
If you don't want that either, you can abuse the replace callback to achieve that in a single pass:
var replaced = false;
var newStr = str.replace(/i/g, function(token){replaced = true; return '!';});

As a workaround you can implement your own callback function that will set a flag and do the replacement. The replacement argument of replace can accept functions.

Comparing the before and after strings is the easiest way to check if it did anything, there's no intrinsic support in String.replace().
[contrived example of how '==' might fail deleted because it was wrong]

Javascript replace is defected by design. Why? It has no compatibility with string replacement in callback.
For example:
"ab".replace(/(a)(b)/, "$1$2")
> "ab"
We want to verify that replace is done in single pass. I was imagine something like:
"ab".replace(/(a)(b)/, "$1$2", function replacing() { console.log('ok'); })
> "ab"
Real variant:
"ab".replace(/(a)(b)/, function replacing() {
console.log('ok');
return "$1$2";
})
> ok
> "$1$2"
But function replacing is designed to receive $0, $1, $2, offset, string and we have to fight with replacement "$1$2". The solution is:
"ab".replace(/(a)(b)/, function replacing() {
console.log('ok');
// arguments are $0, $1, ..., offset, string
return Array.from(arguments).slice(1, -2)
.reduce(function (pattern, match, index) {
// '$1' from strings like '$11 $12' shouldn't be replaced.
return pattern.replace(
new RegExp("\\$" + (index + 1) + "(?=[^\\d]|$)", "g"),
match
);
}, "$1$2");
});
> ok
> "ab"
This solution is not perfect. String replacement itself has its own WATs. For example:
"a".replace(/(a)/, "$01")
> "a"
"a".replace(/(a)/, "$001")
> "$001"
If you want to care about compatibility you have to read spec and implement all its craziness.

If your replace has a different length from the searched text, you can check the length of the string before and after. I know, this is a partial response, valid only on a subset of the problem.
OR
You can do a search. If the search is successfull you do a replace on the substring starting with the found index and then recompose the string. This could be slower because you are generating 3 strings instead of 2.
var test = "Hellllo";
var index = test.search(/ll/);
if (index >= 0) {
test = test.substr(0, index - 1) + test.substr(index).replace(/ll/g, "tt");
}
alert(test);

While this will require multiple operations, using .test() may suffice:
const regex = /foo/;
const yourString = 'foo bar';
if (regex.test(yourString)) {
console.log('yourString contains regex');
// Go ahead and do whatever else you'd like.
}
The test() method executes a search for a match between a regular expression and a specified string. Returns true or false.

With indexOf you can check wether a string contains another string.
Seems like you might want to use that.

have a look at string.match() or string.search()

After doing any RegExp method, read RegExp.lastMatch property:
/^$/.test(''); //Clear RegExp.lastMatch first, Its value will be ''
'abcd'.replace(/bc/,'12');
if(RegExp.lastMatch !== '')
console.log('has been replaced');
else
console.log('not replaced');

Javascript match part of url, if statement based on result

Here is an example of the url i'm trying to match: http://store.mywebsite.com/folder-1/folder-2/item3423434.aspx
What im trying to match is http: //store.mywebsite.com/folder-1 except that "folder-1" will always be a different value. I can't figure out how to write an if statement for this:
Example (pseudo-code)
if(url contains http://store.mywebsite.com/folder-1)
do this
else if (url contains http://store.mywebsite.com/folder-2)
do something else
etc

In the interest of keeping things very simple...
if(location.pathname.indexOf("folder-1") != -1)
{
//do things for "folder-1"
}
this might give you false positives if the value "folder-1" could be present in other parts of the string. If you are already making sure this is not the case, the provided example should be sufficient.

I would split() the string and check an individual component of the url:
var str = "http://store.mywebsite.com/folder-1/folder-2/item3423434.aspx"
// split the string into an array of parts
var spl = str.split("/");
// spl is now [ http:,,store.mywebsite.com,folder-1,folder-2,item3423434.aspx ]
if (spl[4] == "folder-1") {
// do something
} else if (spl[4] == "folder-2") {
// do something else
}
Using this method it's easy to check other parts of the URL too, without having to use a regular expression with sub-expression captures. e.g. matching the second directory in the path would be if spl[5] == "folder-x".
Of course, you could also use indexOf(), which will return the position of a substring match within a string, but this method is not quite as dynamic and it's not very efficient/easy to read if there are going to be a lot of else conditions:
var str = "http://store.mywebsite.com/folder-1/folder-2/item3423434.aspx"
if (str.indexOf("http://store.mywebsite.com/folder-1") === 0) {
// do something
} else if (str.indexOf("http://store.mywebsite.com/folder-2") === 0) {
// do something
}

Assuming the base URL is fixed and the folder numbers can be very large then this code should work:
var url = 'http://store.mywebsite.com/folder-1/folder-2/item3423434.aspx'
, regex = /^http:..store.mywebsite.com.(folder-\d+)/
, match = url.match(regex);
if (match) {
if (match[1] == 'folder-1') {
// Do this
} else if (match[1] == 'folder-2') {
// Do something else
}
}

Just use URL parting in JS and then you can match URL's against simple string conditions or against regular expressions