regular expression to match exactly 5 digits

testing= testing.match(/(\d{5})/g);

I'm reading a full html into variable. From the variable, want to grab out all numbers with the pattern of exactly 5 digits. No need to care of whether before/after this digit having other type of words. Just want to make sure whatever that is 5 digit numbers been grabbed out.

However, when I apply it, it not only pull out number with exactly 5 digit, number with more than 5 digits also retrieved...

I had tried putting ^ in front and $ behind, but it making result come out as null.

I am reading a text file and want to use regex below to pull out numbers with exactly 5 digit, ignoring alphabets.

Try this...

var str = 'f 34 545 323 12345 54321 123456',
    matches = str.match(/\b\d{5}\b/g);

console.log(matches); // ["12345", "54321"]

jsFiddle.

The word boundary \b is your friend here.

Update

My regex will get a number like this 12345, but not like a12345. The other answers provide great regexes if you require the latter.