Regex in JavaScript is not matching a string?

Question

I have this JavaScript code:

var textareas = document.getElementsByTagName('textarea');
var content = textareas[0].value;
var reg = new RegExp(/^.*[[]#.+#[]].*$/mgi);
var res = content.match(reg); // always null

The content var contains a long multiline string that contains patterns like [#some text goes here#]. I tested the regex with some online testing tools and it works against the string. Using the regex in JavaScript fails though - any idea why?

Thanks!

You're using ^ and $ along with the m modifier. So does this mean that you only want to match when the [#some text goes here#] is the only thing on the line? — user1106925
– user1106925, Commented Feb 7, 2012 at 15:47

Susam Pal · Accepted Answer · 2012-02-07 15:45:29Z

4

How about this?

var content = 'foo\nhead [#some text goes here#] tail\nbar';
var reg = new RegExp(/\[#.+#\]/mgi);
var res = content.match(reg);

On execution, res contains the string '[#some text goes here#]'.

Note that I have escaped [ and ]. If they are not escaped, anything enclosed within them forms a character class.

edited Feb 7, 2012 at 15:45

answered Feb 7, 2012 at 15:39

Susam Pal

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2 Comments

user1106925 Over a year ago

@EOB: If it doesn't work for you, then you havent' properly described the result you want.

EOB Over a year ago

Aha, now it works! Dont know what the problem was ... I had the same just with [[] instead of \[ ... propably some tiny mistake somewhere, anyway, it works now, thanks!

Sophie Alpert · Accepted Answer · 2012-02-07 15:43:14Z

1

You used [[] to escape [, which is fine, but you can't use []] to escape ] because it the first ] ends the character class in the regex. This works fine:

/^.*\[#.+#\].*$/mgi

In the case that you only want the single block and not the entire line, use:

/\[#.+#\]/mgi

edited Feb 7, 2012 at 15:43

answered Feb 7, 2012 at 15:37

Sophie Alpert

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1 Comment

EOB Over a year ago

[[] is the same as \[, isnt it?

pete · Accepted Answer · 2012-02-07 15:44:20Z

0

This should capture the text between hashes (e.g., "some text here"):

var reg = /[^\[]*\[#([^\#]+)#\]/gims

answered Feb 7, 2012 at 15:44

pete

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