javascript - Query string of referrer URL

Question

Using php or javascript or regex, is there a quick (one-liner hopefully) to get the query string from the previous (referrer) URL?

Example,

User is at

www.sample.com?one

Then clicks link to go to

www.sample.com?two

From page two... I want to know the previous query string "one."

Answer 1

This perhaps?

var qs = document.referrer.split('?')[1] || '';

Looks like it's a contest :)

var r = document.referrer,
    indexOfQm = r.indexOf('?'),
    len = r.length;

/(?:[^?]+)??(.*)/.exec(r)[1];

r.split('?').shift().pop() || '';

r.slice(indexOfQm === -1? len : indexOfQm - len + 1);

r.substring(indexOfQm === -1? len : indexOfQm + 1);

r.replace(/^.+?(?:?(.*)|$)/, '$1');

r.split('').slice(indexOfQm + 1).join('');

[].reduce.call(r, function (res, c) {
    if (res.found) res.qs += c;
    else if (c === '?') res.found = true;

    return res;
}, { found: false, qs: '' }).qs;