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Regex to replace a string containing variable

I'm new to regex. I got a prob here. I work with xpaths strings. I want to remove a particular element from xpath string if the element has id = myVar
Example:
/html/body/div[3]/div[20]/section[1]/p[5]/span[1][#id="var645932"]/span
I want to replace the /span[1][#id="var645932"]/ with just / if my variable value is equal to id value i.e var645932
I need to do it in javascript. all are strings. I prefer regex. if any regex experts are there Kindly help. am stuck here. is it possible to accomplish it without regex ??
Any help are highly appreciated :) TIA

Try this:
var input = '/html/body/div[3]/div[20]/section[1]/p[5]/span[1][#id="var645932"]/span';
var regex = /\w+\[\w+\]\[\#id="var645932"\]\//gi;
input = input.replace(regex, '');
console.log(input);
Example fiddle
This regex is designed to work even if the structure of the HTML changes, eg:
var input = '/html/body/div[3]/div[20]/section[1]/div[6][#id="var645932"]/span';
If you need to set the id in the regex programmatically, use this:
var regex = new RegExp('/\w+\[\w+\]\[\#id="' + id + '"\]\//', 'gi');

You can use below code -
var expr = '/html/body/div[3]/div[20]/section[1]/p[5]/span[1][#id="var645932"]/span';
var idVal = "var645932";
expr = expr.replace('span[1][#id="'+idVal+'"]/','');
DEMO

Well, you could do it in the following way
var id = "var645932";
var regx = new RegExp('/[^/]+?\\[#id="' + id + '"]/');
var str = '/html/body/div[3]/div[20]/section[1]/p[5]/span[1][#id="var645932"]/span';
console.log(str.replace(regx, "/"));

How to use split in javascript

I have a string like
/abc/def/hij/lmn.o // just a raw string for example dont know what would be the content
I want only /abc/def/hij part of string how do I do that.
I tried using .split() but did not get any solution.

If you want to remove the particular string /lmn.o, you can use replace function, like this
console.log(data.replace("/lmn.o", ""));
# /abc/def/hij
If you want to remove the last part after the /, you can do this
console.log("/" + data.split("/").slice(1, -1).join("/"));
# /abc/def/hij

you can do
var str = "/abc/def/hij/lmn.o";
var dirname = str.replace(/\/[^/]+$/, "");
Alternatively:
var dirname = str.split("/").slice(0, -1).join("/");
See the benchmarks

Using javascript
var x = '/abc/def/hij/lmn.o';
var y = x.substring(0,x.lastIndexOf("/"));
console.log(y);

var s= "/abc/def/hij/lmn.o"
var arr= s.split("/");
after this, use
arr.pop();
to remove the last content of the array which would be lmn.o, after which you can use
var new_s= arr.join("/");
to get /abc/def/hij

Cleaner way to strip specific character places from a string?

I have a var that is set to capture the background-image css property of an element. The result is always like this:
url(http://www.somerandomurltest.net/something/more/things/image.jpg)
I need to get rid of the "url(" and the last ")" so I only am left with the actual url, is there a function that can do this easily? I am currently doing it like this:
var cleanURL = urlVar.substr(0, urlVar.length-1),
cleanURL = cleanURL.substr(4);
Is there a better way?

You can use regex:
var str = "url(http://www.somerandomurltest.net/something/more/things/image.jpg)";
var url = str.match(/url\((.+)\)/)[1];
Example fiddle

You can do this using the slice:
var str = 'url(http://www.somerandomurltest.net/something/more/things/image.jpg)';
str = str.slice(4, -1);
console.log(str);

group parts of a string into an array element

If I have a string... abcdefghi
and I want to use regex to load every elemnent into an array but I want to be able to stick anything connected by plus sign into the same element... how to do that?
var mystring = "abc+d+efghi"
output array ["a","b","cde","f","g","h","i"]

One way to do it:
var re = /([^+])(?:\+[^+])*/g;
var str = 'abcd+e+fghi';
var a = str.match(re).map(function (s) { return s.replace(/\+/g, ''); });
console.log(a);
The value of a[3] should now be 'def'.
http://jsfiddle.net/rbFwR/2

You can use this expression, to produce [a][b][c+d+e][f][g][h][i].
mystring.split ("(.\+)*.")
Next, replace any + characters with empty on the resulting list.

mystring.split("\\+")
Click here for more information.

Remove everything after a certain character

Is there a way to remove everything after a certain character or just choose everything up to that character? I'm getting the value from an href and up to the "?", and it's always going to be a different amount of characters.
Like this
/Controller/Action?id=11112&value=4444
I want the href to be /Controller/Action only, so I want to remove everything after the "?".
I'm using this now:
$('.Delete').click(function (e) {
e.preventDefault();
var id = $(this).parents('tr:first').attr('id');
var url = $(this).attr('href');
console.log(url);
}

You can also use the split() function. This seems to be the easiest one that comes to my mind :).
url.split('?')[0]
jsFiddle Demo
One advantage is this method will work even if there is no ? in the string - it will return the whole string.

var s = '/Controller/Action?id=11112&value=4444';
s = s.substring(0, s.indexOf('?'));
document.write(s);
Sample here
I should also mention that native string functions are much faster than regular expressions, which should only really be used when necessary (this isn't one of those cases).
Updated code to account for no '?':
var s = '/Controller/Action';
var n = s.indexOf('?');
s = s.substring(0, n != -1 ? n : s.length);
document.write(s);
Sample here

var href = "/Controller/Action?id=11112&value=4444";
href = href.replace(/\?.*/,'');
href ; //# => /Controller/Action
This will work if it finds a '?' and if it doesn't

May be very late party :p
You can use a back reference $'
$' - Inserts the portion of the string that follows the matched substring.
let str = "/Controller/Action?id=11112&value=4444"
let output = str.replace(/\?.*/g,"$'")
console.log(output)

It works for me very nicely:
var x = '/Controller/Action?id=11112&value=4444';
var remove_after= x.indexOf('?');
var result = x.substring(0, remove_after);
alert(result);

If you also want to keep "?" and just remove everything after that particular character, you can do:
var str = "/Controller/Action?id=11112&value=4444",
stripped = str.substring(0, str.indexOf('?') + '?'.length);
// output: /Controller/Action?

You can also use the split() method which, to me, is the easiest method for achieving this goal.
For example:
let dummyString ="Hello Javascript: This is dummy string"
dummyString = dummyString.split(':')[0]
console.log(dummyString)
// Returns "Hello Javascript"
Source: https://thispointer.com/javascript-remove-everything-after-a-certain-character/

if you add some json syringified objects, then you need to trim the spaces too... so i add the trim() too.
let x = "/Controller/Action?id=11112&value=4444";
let result = x.trim().substring(0, x.trim().indexOf('?'));

Worked for me:
var first = regexLabelOut.replace(/,.*/g, "");

It can easly be done using JavaScript for reference see link
JS String
EDIT
it can easly done as. ;)
var url="/Controller/Action?id=11112&value=4444 ";
var parameter_Start_index=url.indexOf('?');
var action_URL = url.substring(0, parameter_Start_index);
alert('action_URL : '+action_URL);