Regex to return single attribute from string

Question

Using javascript, can someone please help me with a pattern to match something in this string:

div style="display: none" key="ABC\jones" displaytext="Tom Jones"

My goal is to extract the value for key, in this case: ABC\jones

So, everything between

key="

and

Thanks for the help!!

zellio · Accepted Answer · 2011-06-30 20:38:51Z

14

something like:

/ key="([^"]*)"/

should match

the tailing " is for completeness so that it matches key="..." and not just key="...

As for how this is working, the normal characters are them selves, the [^"] defines a match group of all characters that are not " ( the ^ being not ). So this will match everything after a key=" until it collides with a ". The ( ) capture the matched values for later recall.

edited Jun 30, 2011 at 20:38

answered Jun 30, 2011 at 20:18

zellio

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3 Comments

jensgram Over a year ago

+1 But / key="([^"]*)"/ (leading whitespace) should be considered. I'm not going to make the remark about all the trouble that HTML + regex is bound to give :)

user815460 Over a year ago

It works; thanks very much. can you please help me understand how it works. By the way, it seems to also work without the last double quote character.

rtpHarry Over a year ago

It works like this: ( ) is a capture group, * means repeat looking for characters inside the [] character group, ^" means "not speechmark" so it just keeps going until it hits the end ".

Dan Spiteri · Accepted Answer · 2011-06-30 20:22:56Z

4

Couldn't you just do this?

document.getElementById("my_div").getAttribute("key")

answered Jun 30, 2011 at 20:22

Dan Spiteri

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1 Comment

mpemburn Over a year ago

This will get the id of an element that is already in the DOM. If you need to get it from an HTML string, the regex match method (above) is the way to go.

SBSTP · Accepted Answer · 2011-06-30 20:19:09Z

-1

var str = 'div style="display: none" key="ABC\jones" displaytext="Tom Jones"';

var start = str.indexOf('key="') + 'key="'.length;
var end = str.indexOf('"', start + 1);

var result = str.substring(start, end);

That works... Does it have to be using regex?

answered Jun 30, 2011 at 20:19

SBSTP

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2 Comments

jensgram Over a year ago

Again, str.indexOf(' key="') + ' key="'.length.

user815460 Over a year ago

Thanks, I agree, but I'd like to use a regular expression :-)

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