Develop Reference

JavaScript RegEx match unless wrapped with [nocode][/nocode] tags

My current code is:
var user_pattern = this.settings.tag;
user_pattern = user_pattern.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&"); // escape regex
var pattern = new RegExp(user_pattern.replace(/%USERNAME%/i, "(\\S+)"), "ig");
Where this.settings.tag is a string such as "[user=%USERNAME%]" or "#%USERNAME%". The code uses pattern.exec(str) to find any username in the corresponding tag and works perfectly fine. For example, if str = "Hello, [user=test]" then pattern.exec(str) will find test.
This works fine, but I want to be able to stop it from matching if the string is wrapped in [nocode][/nocode] tags. For example, if str = "[nocode]Hello, [user=test], how are you?[/nocode]" thenpattern.exec(str)` should not match anything.
I'm not quite sure where to start. I tried using a (?![nocode]) before and after the pattern, but to no avail. Any help would be great.

I would just test if the string starts with [nocode] first:
/^\[nocode\]/.test('[nocode]');
Then simply do not process it.

Maybe filter out [nocode] before trying to find the username(s)?
pattern.exec(str.replace(/\[nocode\](.*)\[\/nocode\]/g,''));
I know this isn't exactly what you asked for because now you have to use two separate regular expressions, however code readability is important too and doing it this way is definitely better in that aspect. Hope this helps 😉
JSFiddle: http://jsfiddle.net/1f485Lda/1/
It's based on this: Regular Expression to get a string between two strings in Javascript

Replace a string's special characters using regex

the string looks something like below:
/1/2/3/4 however I want to replace this with ?1=2&3=4.
I am planning to use REReplace in ColdFusion.
Could you suggest me a regex for this ?I also thought of using loops but stuck either way...
Thanks in Advance

A bit cumbersome without making it more manageable using a loop as #Leigh suggested; but you can use the following on string inputs that contain even occurrences of n/m in the format you described:
var s = "/1/2/3/4/5/6";
s.replace(/^\//,'?').replace(/(\d+)\/(\d+)/g,'$1=$2').replace(/\//g,'&')
// => "?1=2&3=4&5=6"

How can i remove http://webservices.rki.dk this in xml

I want to remove namespace in xml.Can you please write regular expression in javascript for the following two strings.I want these two strings in my whole xml.
xmlns="http://webservices.rki.dk"
xmlns="http://webservices.rki.dk/"

You want to use string.replace() to get rid of those. See here.
Example to globally replace in a string (You need to escape some chars to make it work):
var str1 = 'xmlns="http://webservices.rki.dk" hello xmlns="http://webservices.rki.dk"'
var str1Fixed = str1.replace(/xmlns=\"http:\/\/webservices.rki.dk\"/g,"");
alert(str1Fixed);

Omitting special characters from the string using Jquery

I have to implement some type of pixel for analytic and it requires passing a session Id in the url string. My sessionID contains special characters. It looks something like this BFhGlzT6FBkDr2Zndp0!-1309
I need to remove the (-!) characters from this string, how do I achieve this using jquery? I need to make sure jquery remove those characters before it render otherwise it will not report a visit to analytic.
Guys thanks your help but maybe I need to explain bit further, my pixel code look some what like this "
img src="https://sometime.com/png?org_id=k8vif92&session_
id=T6PtTyRSqhGPYBhp84frwth67n6fL7wcLBFhGlzT6FBkDr2Zndp0!-130901808!1319637471144&m=2&m=2" alt="">
Before this pixel fire off, I need to replace the character in the sessionId string to remove !- and keep in mind session id will change every time there is a new session. I need a code that is generic so it works no matter what session id is, it needs to delete special characters from it.

Try using .replace:
var token = "BFhGlzT6FBkDr2Zndp0!-1309";
token.replace(/[^A-Za-z0-9]/g, "");
this will remove any character that's not a letter or number. More concisely:
token.replace(/\W/g, "");
(this won't replace underscores)

Black-listing ! and - (fiddle):
var url = "BFhGlzT6FBkDr2Zndp0!-1309";
document.write(url.replace(/[!\-]/g,""));
White-listing alpha-numeric (fiddle):
var url = "BFhGlzT6FBkDr2Zndp0!-1309";
document.write(url.replace(/[^a-z0-9]/ig,""));

var str = "BFhGlzT6FBkDr2Zndp0!-1309".replace("!-","");
fiddle: http://jsfiddle.net/neilheinrich/eYCjX/

Define a regular expression character set that contains all the allowed characters. For example, yours might look like /[a-zA-Z0-9]/. Now invert it with the complementary character set [^a-zA-Z0-9] and remove all those characters with the String.replace method.
mystring = mystring.replace(/[^a-zA-Z0-9]/g, "");

You dont need jquery for this. You can use javascript regex. See this jsfiddle
var code = "BFhGlzT6FBkDr2Zndp0!-1309";
code = code.replace(/[!-]/g,"");
alert(code);

Shift js string one character

In PHP, it's pretty simple, I'd assume, array_shift($string)?
If not, I'm sure there's some equally simple solution :)
However, is there any way to achieve the same thing in JavaScript?
My specific example is the pulling of window.location.hash from the address bar in order to dynamically load a specific AJAX page. If the hash was "2", i.e. http://foo.bar.com#2...
var hash = window.location.hash; // hash would be "#2"
I'd ideally like to take the # off, so a simple 2 gets fed into the function.
Thanks!

hash = hash.substr(1);
This will take off the first character of hash and return everything else. This is actually similar in functionality to the PHP substr function, which is probably what you should be using to get substrings of strings in PHP rather than array_shift anyway (I didn't even know array_shift would work with strings!)

As you suspected, there's also a shift() function on the Array prototype (MDN).
Strings are not Arrays, they are "array-like objects" so to call shift() on a String, it must be split() first:
var arr = str.split("");
var char = arr.shift();
var originalString = arr.join("");

Building on Ben's point regarding conversion to an Array, given that we are assuming there is only one character as the hash, and that it is the last character, we should really just use:
var hash = window.location.split("").pop();