Javascript RegEx: extract part of an url

Question

        if ((urlStr.indexOf('t='))!=-1)
        {
            var pat = /t=(\d+)m(\d+)s/;
            pat.exec(urlStr);
            alert (RegExp.$1);
            alert (RegExp.$2);

        }

case 1: http://localhost/proc1/commit.php&t=1m13s Returns 1 and 13 -> Okay

case 2: http://localhost/proc1/commit.php&t=13s Returns blank and blank -> Not okay
Expected Result 0 and 13

How do I have to change my regex?

Martin Ender · Accepted Answer · 2012-10-19 08:08:15Z

1

You could try this:

var pat = /t=(?:(\d+)m)?(\d+)s/;

This allows for the first part, including the m to be optional. Now in your second case, $1 should be an empty string.

The (?: makes sure, that you do not get another captured string containing the m.

This will work, too, and do pretty much the same:

var pat = /t=(\d*?)m?(\d+)s/;

Here we just allow the first string of digits to be empty, and m to be optional. Just make sure to use ? after the * to make the repetition ungreedy - otherwise the 1 will be matched by the first repetition, m will be left out, and the 3 will be matched by the second repetition.

edited Oct 19, 2012 at 8:08

answered Oct 19, 2012 at 8:01

Martin Ender

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