Regex replace unterminated parenthetical

Question

I want to replace all unnecessary breaks in a string. I have written a Regex replace but it throws an error: SyntaxError: unterminated parenthetical

var str = "<H1>sdflk</H1><BR><BR><BR><BR><P>test</P><BR><BR><BR><BR>";
str.replace(/((</[a-zA-Z0-9]+>)(<BR>)+)/,"\$2");

But I don't see the missing parenthese.

Welcome to Stack Overflow! Please refrain from parsing HTML with RegEx as it will [drive you insane](http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454). Use an [HTML parser](http://stackoverflow.com/questions/292926/robust-mature-html-parser-for-php) instead. — Madara's Ghost, Jun 29 '12 at 08:51

Igor Chubin · Accepted Answer · 2012-06-29T08:57:07.730

3

You must add \ before / in the re:

/((<\/[a-zA-Z0-9]+>)(<BR>)+)/

Another option is to use RegExp:

re = new RegExp("((</[a-zA-Z0-9]+>)(<BR>)+)");
"<H1>sdflk</H1><BR><BR><BR><BR><P>test</P><BR><BR><BR><BR>".replace(re,"\$1");

edited Jun 29 '12 at 08:57

answered Jun 29 '12 at 08:49

Igor Chubin

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Try also `[/]` instead of `\/` – Igor Chubin Jun 29 '12 at 08:53
Thanks for your solution. I now have the problem that is only replaces the first occurrence in the string. – Willem de Wit Jun 29 '12 at 09:23
The regex doesn't work (even with global and case ignore flags) but good job on the accept – Esailija Jun 29 '12 at 09:24
@WillemdeWit: Just use `new RegExp("(([a-zA-Z0-9]+>)(
)+)", "g")`. (I added `"g"`) – Igor Chubin Jun 29 '12 at 09:27
@Esailija: what do you mean "the regex doesn't work"? The regex works. – Igor Chubin Jun 29 '12 at 09:28
`"
sdflk

test

".replace(/((<\/[a-zA-Z0-9]+>)(
)+)/gi,"\$1"); //"
sdflk

test

"` – Esailija Jun 29 '12 at 09:28
@Esailija: but that is not the same! you will remove br's even when there not closing tags before them! – Igor Chubin Jun 29 '12 at 09:29
@IgorChubin I don't see that requirement anywhere. I would consider 500 brs without a closing tag before the first one unnecessary – Esailija Jun 29 '12 at 09:29
@Esailija: I just explained where is there an error with `missing parenthesis`. I didn't fix the re itself. But I can do it also: just try `\$2` instead of `\$1` – Igor Chubin Jun 29 '12 at 09:32
@Esailija: you should use $2 instead of $1 – Willem de Wit Jun 29 '12 at 09:33
http://jsfiddle.net/z2C86/ I am using `\$2` there with `"g"` and `"i"` even. Yes I suppose the syntax error is fixed. – Esailija Jun 29 '12 at 09:33
The working regex is: `"
sdflk

test

".replace(/((<\/[a-zA-Z0-9]+>)(
)+)/g,'$2');` – Willem de Wit Jun 29 '12 at 09:35

Regex replace unterminated parenthetical

1 Answers1

sdflk

sdflk

sdflk