Develop Reference

regex replace first element

I have the need to replace a HTML string's contents from one <br> to two. But what I can't achieve is when I have one tag following another one:
(<br\s*\/?>)
will match all the tags in this text:
var text = 'text<BR><BR>text text<BR>text;'
will match and with the replace I will have
text = text.replace.replace(/(<br\s*\/?>)>/gi, "<BR\/><BR\/>")
console.log(text); //text<BR/><BR/><BR/><BR/>text text<BR/><BR/>text;"
Is there a way to only increment one tag with the regex? And achieve this:
console.log(text); //text<BR/><BR/><BR/>text text<BR/><BR/>text;"
Or I only will achieve this with a loop?

You may use either
var text = 'text<BR><BR>text text<BR>text;'
text = text.replace(/(<br\s*\/?>)+/gi, "$&$1");
console.log(text); // => text<BR><BR><BR>text text<BR><BR>text;
Here, (<br\s*\/?>)+/gi matches 1 or more sequences of <br>s in a case insensitive way while capturing each tag on its way (keeping the last value in the group beffer after the last it, and "$&$1" will replace with the whole match ($&) and will add the last <br> with $1.
Or
var text = 'text<BR><BR>text text<BR>text;'
text = text.replace(/(?:<br\s*\/?>)+/gi, function ($0) {
return $0.replace(/<br\s*\/?>/gi, "<BR/>") + "<BR/>";
})
console.log(text); // => text<BR/><BR/><BR/>text text<BR/><BR/>text;
Here, the (?:<br\s*\/?>)+ will also match 1 or more <br>s but without capturing each occurrence, and inside the callback, all <br>s will get normalized as <BR/> and a <BR/> will get appended to the result.

You can use negative look ahead (<br\s*\/?>)(?!<br\s*\/?>)/ to increment only the last tag if there are any consecutive:
var text = 'text<BR><BR>text text<BR>text;'
text = text.replace(/(<br\s*\/?>)(?!<br\s*\/?>)/gi, "<BR\/><BR\/>")
console.log(text);

Modify tag position with regex

Suppose I have following string:
var text = "<p>Some text <ins>Text1</p><p>Text2 </ins><ins>Some other text </ins>and another text<ins>Text3</p><p>Text4 </ins></p>"
I need to clean up the above string into
var text = "<p>Some text Text1</p><p><ins>Text2 </ins><ins>Some other text </ins>and another text Text3</p><p><ins>Text4 </ins></p>"
Assume Text1, Text2, Text3, Text4 are random string
I tried below but just mess up:
text.replace(/<ins>(.*?)<\/p><p>/g, '</p><p><ins>');
Thanks
ADDITIONAL EXPLANATION
Take a look at this:
<ins>Text1</p><p>Text2 </ins>
Above is wrong. It should be:
Text1</p><p><ins>Text2 </ins>

Please try the following regex:
function posChange() {
var text = "<p>Some text <ins>Text1</p><p>Text2 </ins><ins>Some other text </ins>and another text<ins>Text3</p><p>Text4 </ins></p>";
var textnew = text.replace(/(<ins>)([^<]+)(<\/p><p>)([^<]+)/g, '$2$3$1$4');
alert(textnew);
}
posChange()
REGEX EXPLANATION:
/(<ins>) 1st capturing group (i.e: <ins>)....$1
([^<]+) 2nd capturing group (i.e: Text1)....$2
(<\/p><p>) 3rd capturing group (i.e: </p><p>)..$3
([^<]+) 4th capturing group (i.e: Text2 )...$4
/g match all occurrences
Based on the requirements, for each match:
Original String: $1 $2 $3 $4
should be replaced with
New String: $2 $3 $1 $4
In this way, the position of each capturing group gets shifted with the help of regex.

You can remove all <ins>:
text = text.replace(/<ins>/g, '');
and then replace every string ending with </ins> and not containing any tag with sum of <ins> and this string:
var matches = text.match(/[^<>]+<\/ins>/g)
for (i = 0; i < matches.length; i++) {
text = text.replace(matches[i], '<ins>' + matches[i]);
}
result:
<p>Some text Text1</p><p><ins>Text2 </ins><ins>Some other text </ins>and another textText3</p><p><ins>Text4 </ins></p>

matching a word from the textarea

I am trying to match words strating with # from a textarea
var start=/#/ig; // # Match
var word=/#(\w+)/ig; //#abc Match
var content=$('#text').val();
var go= content.match(start); //Content Matching #
var name= content.match(word); //Content Matching #abc
Here it checks the value in the text area and gives the output word which starts with #
If there is two matches found it's showing the two matches,but i need only the last match

the .match() function returns an array of matches.
If you want to select the last element, you need to select it like this:
name[name.length-1];
name.length returns the number of elements
-1 because array keys start with 0 and not 1
Here is a fiddle, thanks to Dave Briand

Try this
content = "~test content ~thanks ok ~fine";
strFine = content.lastIndexOf('~');
It gives index for last match character or word or string what you have passed...

The re method match usually returns an array. To get the last match, you can use the following:
var name= content.match(word);
var lastMatch = (!!name) ? name.pop() : name;
If there's no match, the method returns null and you want to be sure you do not try to manipulate null as an array.

What about this?
var text = $('textarea').val(); // "#maxi kcdjnd dcjjncd #ijicd"
//Find all ocurrences of words starting with # and ending in space, period or end of text
var lastMatch = text.match(/(#.*?)(\s|$|\.)/g).pop();
// match returns ["maxi", "#ijicd"]. pop will get the last element

Find previous <p> after nth character?

I want to create a "Read more" button that appears if an elements contains over 1700 characters.
I have achieved this as such:
var textlength = $(this).text().length;
if(textlength > 1700){
$(this).html($(this).html().substring(0, 1700));
$(this).append(readmorelink);
};
This removes all characters after the 1700th. But I would like to remove characters from the 1700th and back to the last </p> tag.
Does anyone know how I can traverse back from an nth character to a specific element?
Fiddle here: http://jsfiddle.net/xvWcH/

Use the lastIndexOf method to find the last occurance of a string before a specific index in the string:
var text = $(this).html();
var index = text.lastIndexOf('</p>', 1700);
$(this).html(text.substring(0, index + 4));

JavaScript Replace Text with HTML Between it

I want to replace some text in a webpage, only the text, but when I replace via the document.body.innerHTML I could get stuck, like so:
HTML:
<p>test test </p>
<p>test2 test2</p>
<p>test3 test3</p>
Js:
var param = "test test test2 test2 test3";
var text = document.body.innerHTML;
document.body.innerHTML = text.replace(param, '*' + param + '*');
I would like to get:
*test test
test2 test2
test3* test3
HTML of 'desired' outcome:
<p>*test test </p>
<p>test2 test2</p>
<p>test3* test3</p>
So If I want to do that with the parameter above ("test test test2 test2 test3") the <p></p> would not be taken into account - resulting into the else section.
How can I replace the text with no "consideration" to the html markup that could be between it?
Thanks in advance.
Edit (for #Sonesh Dabhi):
Basically I need to replace text in a webpage, but when I scan the
webpage with the html in it the replace won't work, I need to scan and
replace based on text only
Edit 2:
'Raw' JavaScript Please (no jQuery)

This will do what you want, it builds a regex expression to find the text between tags and replace in there. Give it a shot.
http://jsfiddle.net/WZYG9/5/
The magic is
(\s*(?:<\/?\w+>)*\s*)*
Which, in the code below has double backslashes to escape them within the string.
The regex itself looks for any number of white space characters (\s). The inner group (?:</?\w+>)* matches any number of start or end tags. ?: tells java script to not count the group in the replacement string, and not remember the matches it finds. < is a literal less than character. The forward slash (which begins an end html tag) needs to be escaped, and the question mark means 0 or 1 occurrence. This is proceeded by any number of white space characters.
Every space within the "text to search" get replaced with this regular expression, allowing it to match any amount of white space and tags between the words in the text, and remember them in the numbered variables $1, $2, etc. The replacement string gets built to put those remembered variables back in.
Which matches any number of tags and whitespace between them.
function wrapTextIn(text, character) {
if (!character) character = "*"; // default to asterik
// trim the text
text = text.replace(/(^\s+)|(\s+$)/g, "");
//split into words
var words = text.split(" ");
// return if there are no words
if (words.length == 0)
return;
// build the regex
var regex = new RegExp(text.replace(/\s+/g, "(\\s*(?:<\\/?\\w+>)*\\s*)*"), "g");
//start with wrapping character
var replace = character;
//for each word, put it and the matching "tags" in the replacement string
for (var i = 0; i < words.length; i++) {
replace += words[i];
if (i != words.length - 1 & words.length > 1)
replace += "$" + (i + 1);
}
// end with the wrapping character
replace += character;
// replace the html
document.body.innerHTML = document.body.innerHTML.replace(regex, replace);
}

WORKING DEMO
USE THAT FUNCTION TO GET TEXT.. no jquery required

First remove tags. i.e You can try document.body.textContent / document.body.innerText or use this example
var StrippedString = OriginalString.replace(/(<([^>]+)>)/ig,"");
Find and replace (for all to be replace add 1 more thing "/g" after search)
String.prototype.trim=function(){return this.replace(/^\s\s*/, '').replace(/\s\s*$/, '');};
var param = "test test test2 test2 test3";
var text = (document.body.textContent || document.body.innerText).trim();
var replaced = text.search(param) >= 0;
if(replaced) {
var re = new RegExp(param, 'g');
document.body.innerHTML = text.replace(re , '*' + param + '*');
} else {
//param was not replaced
//What to do here?
}
See here
Note: Using striping you will lose the tags.