What is the difference in what these 2 are doing? Thx
var m = document.referrer.match(/\&cd=([\d]*)/);
and
var m = document.referrer.match(/cd=(.*?)&/);
Which one is more efficient and effective?
What is the difference in what these 2 are doing? Thx
var m = document.referrer.match(/\&cd=([\d]*)/);
and
var m = document.referrer.match(/cd=(.*?)&/);
Which one is more efficient and effective?
/\&cd=([\d]*)/
- matches any string starting with an "&cd=" followed by any zero or more decimal digits. The first capture group is the decimal digits.
/cd=(.*)&/
- matches any string starting with an "cd=" followed by zero or more characters up to and including the first "&". The first capture group is all characters between "cd=" and "&".
They are similar, but not equivalent. Which one you should use depends on your exact needs. Judging from your comment, it sounds like you want to use:
var m = document.referrer.match(/[?&]cd=(\d+)/);