Question

I’m a bit rusty on my regexp and Javascript. I have the following string var:

var subject = "/admin.php?page=settings&tabs_added[114787535263592]=1&tabs_added[217770811582323]=1&tabs_added[198738186831542]=1"

I want to extract 114787535263592, 217770811582323 and 198738186831542.

I’ve tried to use non-capturing parenthesis (?:) :

var regexp = /(?:tabs_added[\[])(\d)+(?:[\]])/;
var pageid = regexp.exec(subject);

But the result I get (["tabs_added[114787535263592]", "2"]) is not what I expected — what am I doing wrong? Here’s a jsFiddle: http://jsfiddle.net/KgpAw/

Answer 1

You were very close. You need to capture the + as well. Otherwise you only capture one decimal digit:

var regexp = /(?:tabs_added[\[])(\

You should also make your regex global to find all matches:

var regexp = /(?:tabs_added[\[])(\d+)(?:[\]])/g;

Then you should loop through the results, you also don’t need to have non-capturing groups because you’re not using a quantifier on them (?, +, or *), nor do you need to put your [ and ] inside a character class:

var regexp = /tabs_added\[(\d+)\]/g;
var result;
while(null != (result = regexp.exec(subject))){
    document.write(result[1] + '<br />');
} 

JSFiddle Example

Note: It’s better to use console.log for debugging purposes than document.write as long as you have a console available. (Chrome, Opera, IE9, and Firefox have consoles built in, and I think Safari does too, so you should have one available.) console.log provides much more valuable information when logging objects and arrays.