Develop Reference

Trouble with Regular Expression and special charters

I am using a regular Expression for a glosary function on a website, but it can not "handle" special charters as æ, ø and å. The regEx is as follows:
var re = new RegExp("\\b" + pat + "\\b", "g");
How can i modify the RegEx above to handle special charters?

You may use the solution from here:
function getWholeWords(input, word) {
var pL = "a-zA-Z\\xAA\\xB5\\xBA\\xC0-\\xD6\\xD8-\\xF6\\xF8-\\u02C1\\u02C6-\\u02D1\\u02E0-\\u02E4\\u02EC\\u02EE\\u0370-\\u0374\\u0376\\u0377\\u037A-\\u037D\\u037F\\u0386\\u0388-\\u038A\\u038C\\u038E-\\u03A1\\u03A3-\\u03F5\\u03F7-\\u0481\\u048A-\\u052F\\u0531-\\u0556\\u0559\\u0561-\\u0587\\u05D0-\\u05EA\\u05F0-\\u05F2\\u0620-\\u064A\\u066E\\u066F\\u0671-\\u06D3\\u06D5\\u06E5\\u06E6\\u06EE\\u06EF\\u06FA-\\u06FC\\u06FF\\u0710\\u0712-\\u072F\\u074D-\\u07A5\\u07B1\\u07CA-\\u07EA\\u07F4\\u07F5\\u07FA\\u0800-\\u0815\\u081A\\u0824\\u0828\\u0840-\\u0858\\u08A0-\\u08B2\\u0904-\\u0939\\u093D\\u0950\\u0958-\\u0961\\u0971-\\u0980\\u0985-\\u098C\\u098F\\u0990\\u0993-\\u09A8\\u09AA-\\u09B0\\u09B2\\u09B6-\\u09B9\\u09BD\\u09CE\\u09DC\\u09DD\\u09DF-\\u09E1\\u09F0\\u09F1\\u0A05-\\u0A0A\\u0A0F\\u0A10\\u0A13-\\u0A28\\u0A2A-\\u0A30\\u0A32\\u0A33\\u0A35\\u0A36\\u0A38\\u0A39\\u0A59-\\u0A5C\\u0A5E\\u0A72-\\u0A74\\u0A85-\\u0A8D\\u0A8F-\\u0A91\\u0A93-\\u0AA8\\u0AAA-\\u0AB0\\u0AB2\\u0AB3\\u0AB5-\\u0AB9\\u0ABD\\u0AD0\\u0AE0\\u0AE1\\u0B05-\\u0B0C\\u0B0F\\u0B10\\u0B13-\\u0B28\\u0B2A-\\u0B30\\u0B32\\u0B33\\u0B35-\\u0B39\\u0B3D\\u0B5C\\u0B5D\\u0B5F-\\u0B61\\u0B71\\u0B83\\u0B85-\\u0B8A\\u0B8E-\\u0B90\\u0B92-\\u0B95\\u0B99\\u0B9A\\u0B9C\\u0B9E\\u0B9F\\u0BA3\\u0BA4\\u0BA8-\\u0BAA\\u0BAE-\\u0BB9\\u0BD0\\u0C05-\\u0C0C\\u0C0E-\\u0C10\\u0C12-\\u0C28\\u0C2A-\\u0C39\\u0C3D\\u0C58\\u0C59\\u0C60\\u0C61\\u0C85-\\u0C8C\\u0C8E-\\u0C90\\u0C92-\\u0CA8\\u0CAA-\\u0CB3\\u0CB5-\\u0CB9\\u0CBD\\u0CDE\\u0CE0\\u0CE1\\u0CF1\\u0CF2\\u0D05-\\u0D0C\\u0D0E-\\u0D10\\u0D12-\\u0D3A\\u0D3D\\u0D4E\\u0D60\\u0D61\\u0D7A-\\u0D7F\\u0D85-\\u0D96\\u0D9A-\\u0DB1\\u0DB3-\\u0DBB\\u0DBD\\u0DC0-\\u0DC6\\u0E01-\\u0E30\\u0E32\\u0E33\\u0E40-\\u0E46\\u0E81\\u0E82\\u0E84\\u0E87\\u0E88\\u0E8A\\u0E8D\\u0E94-\\u0E97\\u0E99-\\u0E9F\\u0EA1-\\u0EA3\\u0EA5\\u0EA7\\u0EAA\\u0EAB\\u0EAD-\\u0EB0\\u0EB2\\u0EB3\\u0EBD\\u0EC0-\\u0EC4\\u0EC6\\u0EDC-\\u0EDF\\u0F00\\u0F40-\\u0F47\\u0F49-\\u0F6C\\u0F88-\\u0F8C\\u1000-\\u102A\\u103F\\u1050-\\u1055\\u105A-\\u105D\\u1061\\u1065\\u1066\\u106E-\\u1070\\u1075-\\u1081\\u108E\\u10A0-\\u10C5\\u10C7\\u10CD\\u10D0-\\u10FA\\u10FC-\\u1248\\u124A-\\u124D\\u1250-\\u1256\\u1258\\u125A-\\u125D\\u1260-\\u1288\\u128A-\\u128D\\u1290-\\u12B0\\u12B2-\\u12B5\\u12B8-\\u12BE\\u12C0\\u12C2-\\u12C5\\u12C8-\\u12D6\\u12D8-\\u1310\\u1312-\\u1315\\u1318-\\u135A\\u1380-\\u138F\\u13A0-\\u13F4\\u1401-\\u166C\\u166F-\\u167F\\u1681-\\u169A\\u16A0-\\u16EA\\u16F1-\\u16F8\\u1700-\\u170C\\u170E-\\u1711\\u1720-\\u1731\\u1740-\\u1751\\u1760-\\u176C\\u176E-\\u1770\\u1780-\\u17B3\\u17D7\\u17DC\\u1820-\\u1877\\u1880-\\u18A8\\u18AA\\u18B0-\\u18F5\\u1900-\\u191E\\u1950-\\u196D\\u1970-\\u1974\\u1980-\\u19AB\\u19C1-\\u19C7\\u1A00-\\u1A16\\u1A20-\\u1A54\\u1AA7\\u1B05-\\u1B33\\u1B45-\\u1B4B\\u1B83-\\u1BA0\\u1BAE\\u1BAF\\u1BBA-\\u1BE5\\u1C00-\\u1C23\\u1C4D-\\u1C4F\\u1C5A-\\u1C7D\\u1CE9-\\u1CEC\\u1CEE-\\u1CF1\\u1CF5\\u1CF6\\u1D00-\\u1DBF\\u1E00-\\u1F15\\u1F18-\\u1F1D\\u1F20-\\u1F45\\u1F48-\\u1F4D\\u1F50-\\u1F57\\u1F59\\u1F5B\\u1F5D\\u1F5F-\\u1F7D\\u1F80-\\u1FB4\\u1FB6-\\u1FBC\\u1FBE\\u1FC2-\\u1FC4\\u1FC6-\\u1FCC\\u1FD0-\\u1FD3\\u1FD6-\\u1FDB\\u1FE0-\\u1FEC\\u1FF2-\\u1FF4\\u1FF6-\\u1FFC\\u2071\\u207F\\u2090-\\u209C\\u2102\\u2107\\u210A-\\u2113\\u2115\\u2119-\\u211D\\u2124\\u2126\\u2128\\u212A-\\u212D\\u212F-\\u2139\\u213C-\\u213F\\u2145-\\u2149\\u214E\\u2183\\u2184\\u2C00-\\u2C2E\\u2C30-\\u2C5E\\u2C60-\\u2CE4\\u2CEB-\\u2CEE\\u2CF2\\u2CF3\\u2D00-\\u2D25\\u2D27\\u2D2D\\u2D30-\\u2D67\\u2D6F\\u2D80-\\u2D96\\u2DA0-\\u2DA6\\u2DA8-\\u2DAE\\u2DB0-\\u2DB6\\u2DB8-\\u2DBE\\u2DC0-\\u2DC6\\u2DC8-\\u2DCE\\u2DD0-\\u2DD6\\u2DD8-\\u2DDE\\u2E2F\\u3005\\u3006\\u3031-\\u3035\\u303B\\u303C\\u3041-\\u3096\\u309D-\\u309F\\u30A1-\\u30FA\\u30FC-\\u30FF\\u3105-\\u312D\\u3131-\\u318E\\u31A0-\\u31BA\\u31F0-\\u31FF\\u3400-\\u4DB5\\u4E00-\\u9FCC\\uA000-\\uA48C\\uA4D0-\\uA4FD\\uA500-\\uA60C\\uA610-\\uA61F\\uA62A\\uA62B\\uA640-\\uA66E\\uA67F-\\uA69D\\uA6A0-\\uA6E5\\uA717-\\uA71F\\uA722-\\uA788\\uA78B-\\uA78E\\uA790-\\uA7AD\\uA7B0\\uA7B1\\uA7F7-\\uA801\\uA803-\\uA805\\uA807-\\uA80A\\uA80C-\\uA822\\uA840-\\uA873\\uA882-\\uA8B3\\uA8F2-\\uA8F7\\uA8FB\\uA90A-\\uA925\\uA930-\\uA946\\uA960-\\uA97C\\uA984-\\uA9B2\\uA9CF\\uA9E0-\\uA9E4\\uA9E6-\\uA9EF\\uA9FA-\\uA9FE\\uAA00-\\uAA28\\uAA40-\\uAA42\\uAA44-\\uAA4B\\uAA60-\\uAA76\\uAA7A\\uAA7E-\\uAAAF\\uAAB1\\uAAB5\\uAAB6\\uAAB9-\\uAABD\\uAAC0\\uAAC2\\uAADB-\\uAADD\\uAAE0-\\uAAEA\\uAAF2-\\uAAF4\\uAB01-\\uAB06\\uAB09-\\uAB0E\\uAB11-\\uAB16\\uAB20-\\uAB26\\uAB28-\\uAB2E\\uAB30-\\uAB5A\\uAB5C-\\uAB5F\\uAB64\\uAB65\\uABC0-\\uABE2\\uAC00-\\uD7A3\\uD7B0-\\uD7C6\\uD7CB-\\uD7FB\\uF900-\\uFA6D\\uFA70-\\uFAD9\\uFB00-\\uFB06\\uFB13-\\uFB17\\uFB1D\\uFB1F-\\uFB28\\uFB2A-\\uFB36\\uFB38-\\uFB3C\\uFB3E\\uFB40\\uFB41\\uFB43\\uFB44\\uFB46-\\uFBB1\\uFBD3-\\uFD3D\\uFD50-\\uFD8F\\uFD92-\\uFDC7\\uFDF0-\\uFDFB\\uFE70-\\uFE74\\uFE76-\\uFEFC\\uFF21-\\uFF3A\\uFF41-\\uFF5A\\uFF66-\\uFFBE\\uFFC2-\\uFFC7\\uFFCA-\\uFFCF\\uFFD2-\\uFFD7\\uFFDA-\\uFFDC";
var rx = RegExp("(?:^|[^_0-9" + pL + "])(" + word + ")(?![_0-9" + pL + "])", "ig"); // Build the regex (might be moved out from the function)
var words = [];
while ((m = rx.exec(input)) !== null) {
words.push(m[1]); // Add an occurrence
}
return words;
}
var word = "æøå";
var input = "æøå, AæøåZ, BæøåY, and æøå!";
document.body.innerHTML = "<pre>" + JSON.stringify(getWholeWords(input, word), 0, 4) + "</pre>";
Or a regex that will look for a word only if it is enclosed with whitespace/start/end of the string:
var re = new RegExp("(?:^|\\s)(" + pat.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&') + ")(?!\\S)", "g");
and grab Group 1 value.

Javascript regex replace yields unexpected result

I have this strange issue, hope that someone will explain what is going on.
My intention is to capture the textual part (a-z, hyphen, underscore) and append the numeric values of id and v to it, underscore separated.
My code:
var str_1 = 'foo1_2';
var str_2 = 'foo-bar1_2';
var str_3 = 'foo_baz1_2';
var id = 3;
var v = 2;
str_1 = str_1.replace(/([a-z_-]+)\d+/,'$1' + id + '_' + v);
str_2 = str_2.replace(/([a-z_-]+)\d+/,'$1' + id + '_' + v);
str_3 = str_3.replace(/([a-z_-]+)\d+/,'$1' + id + '_' + v);
$('#test').html(str_1 + '<br>' + str_2 + '<br>' + str_3 + '<br>');
Expected result:
foo3_2
foo-bar3_2
foo_baz3_2
Actual Result:
foo3_2_2
foo-bar3_2_2
foo_baz3_2_2
Any ideas?
JS Fiddle example

Your pattern:
/([a-z_-]+)\d+/
matches only "foo1" in "foo1_2", and "foo" will be the value of the captured group. The .replace() function replaces the portion of the source string that was actually matched, leaving the remainder alone. Thus "foo1" is replaced by "foo3_2", but the original trailing "_2" is still there as well.
If you want to alter the entire string, then your regular expression will have to account for everything in the source strings.

Just try with:
str_1 = str_1.match(/([a-z_-]+)\d+/)[1] + id + '_' + v;

Use this instead to capture 1_2 completely:
str_1 = str_1.replace(/([a-z_-]+)\d+_\d+/,'$1' + id + '_' + v);

Because you want to replace _2 also of string. Solution can be this:
str_1 = str_1.replace(/([a-z_-]+)\d+_\d/,'$1' + id + '_' + v);
str_2 = str_2.replace(/([a-z_-]+)\d+_\d/,'$1' + id + '_' + v);
str_3 = str_3.replace(/([a-z_-]+)\d+_\d/,'$1' + id + '_' + v);
DEMO

Your pattern actually includes the first digits, but it will store only the textual part into $1:
foo1_2
([a-z_-]+)\d+ = foo1
$1 = foo
The pattern stops searching at the first digits of the string.
if you want to replace any characters after the textual part, you could use this pattern:
/([a-z_-]+)\d+.*/

Replacing all occurences in a string in javascript issue

This is my js code:
html = html.replace("/["+increment+"]/gi", '[' + counter + ']');
where increment is 0 and counter is 1
or
html = html.replace("/[0]/gi", '[1]');
My version does not replace the [0] with [1] in my string. Why ?

You need to use the RegExp constructor as the regex is dynamic
var regex = new RegExp("\\[" + increment + "\\]", 'gi')
html = html.replace(regex, '[' + counter + ']');
Also you could sanitize the dynamic variable if you want
if (!RegExp.escape) {
//A escape function to sanitize special characters in the regex
RegExp.escape = function (value) {
return value.replace(/[\-\[\]{}()*+?.,\\\^$|#\s]/g, "\\$&")
};
}
//You could also escape the dynamic value it is an user input
var regex = new RegExp("\\[" + RegExp.escape(increment) + "\\]", 'gi')
html = html.replace(regex, '[' + counter + ']');

Use this way:
html = html.replace(new RegExp("\\["+increment+"\\]", "gi"), '[' + counter + ']');
This makes use of the dynamic values.

generic regexp using jquery variable to replace dot, colon or any other character

I have a jquery code that trims the leading and trailing character (passed from the calling program). I am using a variable in RegExp to replace the character with blank. How can I make the RegExp work for any character passed from the calling program? Here is the simplified code:
var time = ":1h:45m:34s:";
var chr= ':'; //can have . or , or any other character
var regex = new RegExp("(^" + chr + ")|(" + chr+ "$)" , "g"); //works for colon but not for dot.
//var regex = new RegExp("(^/" + chr + ")|(/" + chr+ "$)" , "g"); //for dot I added / but not for colon.
var formattedtime = time.replace(regex, "");
Expected Outputs:
1. time = ":1h:45m:34s:";
chr = ":";
Output: 1h:45m:34s
2. time = "1h:45m:34s";
chr = ":";
Output: 1h:45m:34s
3. time = ".45m.34s";
chr = ".";
Output: 45m.34s
4. time = "1h.45m.34s.";
chr = ".";
Output: 1h.45m.34s
How can I make the regexp work for any character?

You need to escape meta characters (like . and several others) to get literals. You do that by adding a backslash before them.
JS doesn't have any built in function for that, so you could use this:
function quotemeta(str){
return str.replace(/[.+*?|\\^$(){}\[\]-]/g, '\\$&');
}
Used like so:
new RegExp("^(?:" + quotemeta(chr) + ")+|(?:" + quotemeta(chr) + ")+$" , "g");

var chr= ':/';
...
var regex = new RegExp("(^[" + chr + "])|([" + chr+ "]$)" , "g");

Regex should this way:-
For Colon, /^(\:)|(\:)$/gim
For Dot, /^(\.)|(\.)$/gim
OR
/^(\:|\w|\.)|(\:|\w|\.)$/gim
LIVE DEMO

Search and replace specific query string parameter value in javascript

I have a string which is something like this :
a_href= "www.google.com/test_ref=abc";
I need to search for test_ref=abc in thisabove strinng and replace it with new value
var updated_test_ref = "xyz";
a_href ="www.google.com/test_ref=updated_test_ref"
i.e
www.google.com/test_ref=xyz.
How can we do this ?
EDIT:
test_ref value can be a URL link in itself something like http://google.com?param1=test1&param2=test2. I need to capture complete value not till first &.

a_href = a_href.replace(/(test_ref=)[^\&]+/, '$1' + updated_test_ref);

Based on this discussion I have fixed the Chris function (problem with regex string!)
function updateUrlParameter(url, param, value){
var regex = new RegExp('('+param+'=)[^\&]+');
return url.replace( regex , '$1' + value);
}

Based on this discussion I have created a references function. enjoy
updateUrlParameter(url, param, value){
var regex = new RegExp("/([?|&]" + param + "=)[^\&]+/");
return url.replace(regex, '$1' + value);
}

I was searching for this solution for few hours and finally stumbled upon this question. I have tried all the solutions here. But there is still an issue while replacing specific param value in url.
Lets take a sample url like
http://google.com?param1=test1&param2=test2&anotherparam1=test3
and the updated url should be like
http://google.com?param1=newtest&param2=test2&anotherparam1=test3, where value of param1 is changed.
In this case, as #Panthro has pointed out, adding [?|&] before the querying string ensures that anotherparam1 is not replaced. But this solution also adds the '?' or '&' character to the matching string. So while replacing the matched characters, the '?' or '&' will also get replaced. You will not know exactly which character is replaced so you cannot append that character as well.
The solution is to match '?' or '&' as preceding characters only.
I have re-written the function of #Chris, fixing the issue with string and have added case insensitive argument.
updateUrlParameter(url, param, value){
var regex = new RegExp('(?<=[?|&])(' + param + '=)[^\&]+', 'i');
// return url.replace(regex, param + '=$1' + value);
return url.replace(regex, param + '=' + value);
}
Here (?<=[?|&]) means, the regex will match '?' or '&' char and will take the string that occurs after the specified character (looks behind the character). That means only param1=test1 substring will be matched and replaced.

I know this is a bit dirty code but I've achieved what I was looking for. It replaces the given query string or adds new one if it doesn't exist yet.
function updateUrlParameter(url, param, value) {
var index = url.indexOf("?");
if (index > 0) {
var u = url.substring(index + 1).split("&");
var params = new Array(u.length);
var p;
var found = false;
for (var i = 0; i < u.length; i++) {
params[i] = u[i].split("=");
if (params[i][0] === param) {
params[i][1] = value;
found = true;
}
}
if (!found) {
params.push(new Array(2));
params[params.length - 1][0] = param;
params[params.length - 1][1] = value;
}
var res = url.substring(0, index + 1) + params[0][0] + "=" + params[0][1];
for (var i = 1; i < params.length; i++) {
res += "&" + params[i][0] + "=" + params[i][1];
}
return res;
} else {
return url + "?" + param + "=" + value;
}
}
It will work when given regular URL addresses like:
updateUrlParameter('https://www.example.com/some.aspx?mid=1&id=2','id','5');
updateUrlParameter('https://www.example.com/?mid=1&id=2','id','5');
updateUrlParameter('https://www.example.com/some.aspx','id','5');
Please note It will NOT work only if any of the query string parameter name or value contains "=" and/or "&" chars. It will work just fine behind that.

*Java script code to find a specific query string and replace its value *
('input.letter').click(function () {
//0- prepare values
var qsTargeted = 'letter=' + this.value; //"letter=A";
var windowUrl = '';
var qskey = qsTargeted.split('=')[0];
var qsvalue = qsTargeted.split('=')[1];
//1- get row url
var originalURL = window.location.href;
//2- get query string part, and url
if (originalURL.split('?').length > 1) //qs is exists
{
windowUrl = originalURL.split('?')[0];
var qs = originalURL.split('?')[1];
//3- get list of query strings
var qsArray = qs.split('&');
var flag = false;
//4- try to find query string key
for (var i = 0; i < qsArray.length; i++) {
if (qsArray[i].split('=').length > 0) {
if (qskey == qsArray[i].split('=')[0]) {
//exists key
qsArray[i] = qskey + '=' + qsvalue;
flag = true;
break;
}
}
}
if (!flag)// //5- if exists modify,else add
{
qsArray.push(qsTargeted);
}
var finalQs = qsArray.join('&');
//6- prepare final url
window.location = windowUrl + '?' + finalQs;
}
else {
//6- prepare final url
//add query string
window.location = originalURL + '?' + qsTargeted;
}
})
});