How to read GET data from a URL using JavaScript?

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Please see this, more current solution before using a custom parsing function like below, or a 3rd party library.

The a code below works and is still useful in situations where URLSearchParams is not available, but it was written in a time when there was no native solution available in JavaScript. In modern browsers or Node.js, prefer to use the built-in functionality.

function parseURLParams(url) {
    var queryStart = url.indexOf("?") + 1,
        queryEnd   = url.indexOf("#") + 1 || url.length + 1,
        query = url.slice(queryStart, queryEnd - 1),
        pairs = query.replace(/\+/g, " ").split("&"),
        parms = {}, i, n, v, nv;

    if (query === url || query === "") return;

    for (i = 0; i < pairs.length; i++) {
        nv = pairs[i].split("=", 2);
        n = decodeURIComponent(nv[0]);
        v = decodeURIComponent(nv[1]);

        if (!parms.hasOwnProperty(n)) parms[n] = [];
        parms[n].push(nv.length === 2 ? v : null);
    }
    return parms;
}

Use as follows:

var urlString = "http://www.example.com/bar?a=a+a&b%20b=b&c=1&c=2&d#hash";
    urlParams = parseURLParams(urlString);

which returns a an object like this: 

{
  "a"  : ["a a"],     /* param values are always returned as arrays */
  "b b": ["b"],       /* param names can have special chars as well */
  "c"  : ["1", "2"]   /* an URL param can occur multiple times!     */
  "d"  : [null]       /* parameters without values are set to null  */ 
}

So

parseURLParams("www.mints.com?name=something")

gives

{name: ["something"]}

EDIT: The original version of this answer used a regex-based approach to URL-parsing. It used a shorter function, but the approach was flawed and I replaced it with a proper parser.

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