Develop Reference

Replace with RegExp only outside tags in the string

I have a strings where some html tags could present, like
this is a nice day for bowling <b>bbbb</b>
how can I replace with RegExp all b symbols, for example, with :blablabla: (for example) but ONLY outside html tags?
So in that case the resulting string should become
this is a nice day for :blablabla:owling <b>bbbb</b>
EDIT: I would like to be more specific, based on the answers I have received. So first of all I have just a string, not DOM element, or anything else. The string may or may not contain tags (opening and closing). The main idea is to be able to replace anywhere in the text except inside tags. For example if I have a string like
not feeling well today :/ check out this link http://example.com
the regexp should replace only first :/ with real smiley image, but should not replace second and third, because they are inside (and part of) tag. Here's an example snippet using the regexp from one of the answer.
var s = 'not feeling well today :/ check out this link http://example.com';
var replaced = s.replace(/(?:<[^\/]*?.*?<\/.*?>)|(:\/)/g, "smiley_image_here");
document.querySelector("pre").textContent = replaced;
<pre></pre>
It is strange but the DEMO shows that it captured the correct group, but the same regexp in replace function seem not to be working.

The regex itself to replace all bs with :blablabla: is not that hard:
.replace(/b/g, ":blablabla:")
It is a bit tricky to get the text nodes where we need to perform search and replace.
Here is a DOM-based example:
function replaceTextOutsideTags(input) {
var doc = document.createDocumentFragment();
var wrapper = document.createElement('myelt');
wrapper.innerHTML = input;
doc.appendChild( wrapper );
return textNodesUnder(doc);
}
function textNodesUnder(el){
var n, walk=document.createTreeWalker(el,NodeFilter.SHOW_TEXT,null,false);
while(n=walk.nextNode())
{
if (n.parentNode.nodeName.toLowerCase() === 'myelt')
n.nodeValue = n.nodeValue.replace(/:\/(?!\/)/g, "smiley_here");
}
return el.firstChild.innerHTML;
}
var s = 'not feeling well today :/ check out this link http://example.com';
console.log(replaceTextOutsideTags(s));
Here, we only modify the text nodes that are direct children of the custom-created element named myelt.
Result:
not feeling well today smiley_here check out this link http://example.com

var input = "this is a nice day for bowling <b>bbbb</b>";
var result = input.replace(/(^|>)([^<]*)(<|$)/g, function(_,a,b,c){
return a
+ b.replace(/b/g, ':blablabla:')
+ c;
});
document.querySelector("pre").textContent = result;
<pre></pre>
You can do this:
var result = input.replace(/(^|>)([^<]*)(<|$)/g, function(_,a,b,c){
return a
+ b.replace(/b/g, ':blablabla:') // you may do something else here
+ c;
});
Note that in most (no all but most) real complex use cases, it's much more convenient to manipulate a parsed DOM rather than just a string. If you're starting with a HTML page, you might use a library (some, like my one, accept regexes to do so).

I think you can use a regex like this : (Just for a simple data not a nested one)
/<[^\/]*?b.*?<\/.*?>|(b)/ig
[Regex Demo]
If you wanna use a regex I can suggest you use below regex to remove all tags recursively until all tags removed:
/<[^\/][^<]*>[^<]*<\/.*?>/g
then use a replace for finding any b.

Javascript Regex only replacing first match occurence

I am using regular expressions to do some basic converting of wiki markup code into copy-pastable plain text, and I'm using javascript to do the work.
However, javascript's regex engine behaves much differently to the ones I've used previously as well as the regex in Notepad++ that I use on a daily basis.
For example- given a test string:
==Section Header==
===Subsection 1===
# Content begins here.
## Content continues here.
I want to end up with:
Section Header
Subsection 1
# Content begins here.
## Content continues here.
Simply remove all equals signs.
I began with the regex setup of:
var reg_titles = /(^)(=+)(.+)(=+)/
This regex searches for lines that begin with one or more equals with another set of one or more equals. Rubular shows that it matches my lines accurately and does not catch equals signs in the middle of contet. http://www.rubular.com/r/46PrkPx8OB
The code to replace the string based on regex
var lines = $('.tb_in').val().split('\n'); //use jquery to grab text in a textarea, and split into an array of lines based on the \n
for(var i = 0;i < lines.length;i++){
line_temp = lines[i].replace(reg_titles, "");
lines[i] = line_temp; //replace line with temp
}
$('.tb_out').val(lines.join("\n")); //rejoin and print result
My result is unfortunately:
Section Header==
Subsection 1===
# Content begins here.
## Content continues here.
I cannot figure out why the regex replace function, when it finds multiple matches, seems to only replace the first instance it finds, not all instances.
Even when my regex is updated to:
var reg_titles = /(={2,})/
"Find any two or more equals", the output is still identical. It makes a single replacement and ignores all other matches.
No one regex expression executor behaves this way for me. Running the same replace multiple times has no effect.
Any advice on how to get my string replace function to replace ALL instances of the matched regex instead of just the first one?

^=+|=+$
You can use this.Do not forget to add g and m flags.Replace by ``.See demo.
http://regex101.com/r/nA6hN9/28

Add the g modifier to do a global search:
var reg_titles = /^(=+)(.+?)(=+)/g

Your regex is needlessly complex, and yet doesn't actually accomplish what you set out to do. :) You might try something like this instead:
var reg_titles = /^=+(.+?)=+$/;
lines = $('.tb_in').val().split('\n');
lines.forEach(function(v, i, a) {
a[i] = v.replace(reg_titles, '$1');
})
$('.tb_out').val(lines.join("\n"));

JS / RegEx to remove characters grouped within square braces

I hope I can explain myself clearly here and that this is not too much of a specific issue.
I am working on some javascript that needs to take a string, find instances of chars between square brackets, store any returned results and then remove them from the original string.
My code so far is as follows:
parseLine : function(raw)
{
var arr = [];
var regex = /\[(.*?)]/g;
var arr;
while((arr = regex.exec(raw)) !== null)
{
console.log(" ", arr);
arr.push(arr[1]);
raw = raw.replace(/\[(.*?)]/, "");
console.log(" ", raw);
}
return {results:arr, text:raw};
}
This seems to work in most cases. If I pass in the string [id1]It [someChar]found [a#]an [id2]excellent [aa]match then it returns all the chars from within the square brackets and the original string with the bracketed groups removed.
The problem arises when I use the string [id1]It [someChar]found [a#]a [aa]match.
It seems to fail when only a single letter (and space?) follows a bracketed group and starts missing groups as you can see in the log if you try it out. It also freaks out if i use groups back to back like [a][b] which I will need to do.
I'm guessing this is my RegEx - begged and borrowed from various posts here as I know nothing about it really - but I've had no luck fixing it and could use some help if anyone has any to offer. A fix would be great but more than that an explanation of what is actually going on behind the scenes would be awesome.
Thanks in advance all.

You could use the replace method with a function to simplify the code and run the regexp only once:
function parseLine(raw) {
var results = [];
var parsed = raw.replace(/\[(.*?)\]/g, function(match,capture) {
results.push(capture);
return '';
});
return { results : results, text : parsed };
}

The problem is due to the lastIndex property of the regex /\[(.*?)]/g; not resetting, since the regex is declared as global. When the regex has global flag g on, lastIndex property of RegExp is used to mark the position to start the next attempt to search for a match, and it is expected that the same string is fed to the RegExp.exec() function (explicitly, or implicitly via RegExp.test() for example) until no more match can be found. Either that, or you reset the lastIndex to 0 before feeding in a new input.
Since your code is reassigning the variable raw on every loop, you are using the wrong lastIndex to attempt the next match.
The problem will be solved when you remove g flag from your regex. Or you could use the solution proposed by Tibos where you supply a function to String.replace() function to do replacement and extract the capturing group at the same time.

You need to escape the last bracket: \[(.*?)\].

Skipping over tags and spaces in regex html

I'm using this regex to find a String that starts with !?, ends with ?!, and has another variable inbetween (in this example "a891d050"). This is what I use:
var pattern = new RegExp(/!\\?.*\s*(a891d050){1}.*\s*\\?!/);
It matches correctly agains this one:
!?v8qbQ5LZDnFLsny7VmVe09HJFL1/WfGD2A:::a891d050?!
But fails when the string is broken up with html tags.
<span class="userContent"><span>!?v8qbQ5LZDnFLsny7VmVe09HJFL1/</span><wbr /><span class="word_break"></span>WfGD2A:::a891d050?!</span></div></div></div></div>
I tried adding \s and {space}*, but it still fails.
The question is, what (special?)characters do I need to account for if I want to ignore whitespace and html tags in my match.
edit: this is how I use the regex:
var pattern = /!\?[\s\S]*a891d050[\s\S]*\?!/;
document.body.innerHTML = document.body.innerHTML.replace(pattern,"new content");
It appears to me that when it encounters the 'plain' string it replaces is correctly. But when faced with String with classes around it and inside, it makes a mess of the classes or doesn't replace at all depending on the context. So I decided to try jquery-replacetext-plugin(as it promises to leave tags as they were) like this:
$("body *").replaceText( pattern, "new content" );
But with no success, the results are the same as before.

Maybe this:
var pattern = /!\?[\s\S]*a891d050[\s\S]*\?!/;
[\s\S] should match any character. I have also removed {1}.

The problem was apparently solved by using this regex:
var pattern = /(!\?)(?:<(?:"[^"]*"['"]*|'[^']*'['"]*|[^'">])*?>)?(.)*?(a891d050)(?:<(?:"[^"]*"['"]*|'[^']*'['"]*|[^'">])*?>)?(.)*?(\?!)/;

Need to replace "$" to "_" with Javascript

I´ve got the following string from a .getAttribute():
ctl00$m$g_ff7ec6ac_ec2e_4402_aaaa_7fcce245ff1b$ctl03$_UserName
Let´s call it "String". Now I need to replace the $ to a _ . I tried:
String.replace(/\$/g, "\_");
... doesn´t work.
Second try:
String.replace(/$$/g, "\_");
... doesn´t work.
Third try:
String.replace(/\$$/g, "\_");
... doesn´t work.
So... Ca anyone help? Thanks for all effort!
EDIT: Need to get it work for IE8/9
The code at this time:
mailName = document.body.innerHTML.match(/ctl00\$.+EmailAddress/);
alert(mailName); // String is "ctl00$m$g_ff7ec6ac_ec2e_4402_aaaa_7fcce245ff1b$ctl03$_UserName"
mailName2 = mailName.replace(/\$/g, "_");
EDIT2:
... I´va got the answer one my own.
mailName = document.body.innerHTML.match(/ctl00\$.+EmailAddress/);
gives a string back but .replace() or .split() won´t work with it. To get ot work you need to do it like this
mailID = '"' + document.body.innerHTML.match(/ctl00\$.+EmailAddress/) + '"';
after that everything is fine. Don´t know why, but in IE8/9 this solution works great.

Use
yourString = yourString.replace(/\$/g, "_");
No need to escape the second string.
From the MDN :
Returns a new string with some or all matches of a pattern replaced by
a replacement. The pattern can be a string or a RegExp, and the
replacement can be a string or a function to be called for each match.
Note also that replace doesn't change the original string. You need to get back the returned value.
And, regarding your edit, note that the match function of Internet Explorer seems to return an array even without the g modifier :
If the match method does not find a match, it returns null. If it
finds a match, match returns an array, and the properties of the
global RegExp object are updated to reflect the results of the match.
You can do
var str = ''+ document.body.innerHTML.match(/ctl00\$.+EmailAddress/);
Demonstration