JavaScript query string [closed]

Answer 1

You can extract the key/value pairs from the location.search property, this property has the part of the URL that follows the ? symbol, including the ? symbol.

function getQueryString() {
  var result = {}, queryString = location.search.slice(1),
      re = /([^&=]+)=([^&]*)/g, m;

  while (m = re.exec(queryString)) {
    result[decodeURIComponent(m[1])] = decodeURIComponent(m[2]);
  }

  return result;
}

// ...
var myParam = getQueryString()["myParam"];

Answer 2

It is worth noting, the library that John Slegers mentioned does have a jQuery dependency, however here is a version that is vanilla Javascript.

https://github.com/EldonMcGuinness/querystring.js

I would have simply commented on his post, but I lack the reputation to do so. :/

Example:

The example below process the following, albeit irregular, query string:

?foo=bar&foo=boo&roo=bar;bee=bop;=ghost;=ghost2;&;checkbox%5B%5D=b1;checkbox%5B%5D=b2;dd=;http=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab&http=http%3A%2F%2Fw3schools2.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab 

var qs = "?foo=bar&foo=boo&roo=bar;bee=bop;=ghost;=ghost2;&;checkbox%5B%5D=b1;checkbox%5B%5D=b2;dd=;http=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab&http=http%3A%2F%2Fw3schools2.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab";
//var qs = "?=&=";
//var qs = ""

var results = querystring(qs);

(document.getElementById("results")).innerHTML =JSON.stringify(results, null, 2);

<script 
src="https://rawgit.com/EldonMcGuinness/querystring.js/master/dist/querystring.min.js"></script>
<pre id="results">RESULTS: Waiting...</pre>

Answer 3

The code

This Gist by Eldon McGuinness is by far the most complete implementation of a JavaScript query string parser that I've seen so far.

Unfortunately, it's written as a jQuery plugin.

I rewrote it to vanilla JS and made a few improvements :

function parseQuery(str) {
  var qso = {};
  var qs = (str || document.location.search);
  // Check for an empty querystring
  if (qs == "") {
    return qso;
  }
  // Normalize the querystring
  qs = qs.replace(/(^\?)/, '').replace(/;/g, '&');
  while (qs.indexOf("&&") != -1) {
    qs = qs.replace(/&&/g, '&');
  }
  qs = qs.replace(/([\&]+$)/, '');
  // Break the querystring into parts
  qs = qs.split("&");
  // Build the querystring object
  for (var i = 0; i < qs.length; i++) {
    var qi = qs[i].split("=");
    qi = qi.map(function(n) {
      return decodeURIComponent(n)
    });
    if (typeof qi[1] === "undefined") {
      qi[1] = null;
    }
    if (typeof qso[qi[0]] !== "undefined") {

      // If a key already exists then make this an object
      if (typeof (qso[qi[0]]) == "string") {
        var temp = qso[qi[0]];
        if (qi[1] == "") {
          qi[1] = null;
        }
        qso[qi[0]] = [];
        qso[qi[0]].push(temp);
        qso[qi[0]].push(qi[1]);

      } else if (typeof (qso[qi[0]]) == "object") {
        if (qi[1] == "") {
          qi[1] = null;
        }
        qso[qi[0]].push(qi[1]);
      }
    } else {
      // If no key exists just set it as a string
      if (qi[1] == "") {
        qi[1] = null;
      }
      qso[qi[0]] = qi[1];
    }
  }
  return qso;
}

How to use it

var results = parseQuery("?foo=bar&foo=boo&roo=bar;bee=bop;=ghost;=ghost2;&;checkbox%5B%5D=b1;checkbox%5B%5D=b2;dd=;http=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab&http=http%3A%2F%2Fw3schools2.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab");

Output

{
  "foo": ["bar", "boo" ],
  "roo": "bar",
  "bee": "bop",
  "": ["ghost", "ghost2"],
  "checkbox[]": ["b1", "b2"],
  "dd": null,
  "http": [
    "http://w3schools.com/my test.asp?name=ståle&car=saab",
    "http://w3schools2.com/my test.asp?name=ståle&car=saab"
  ]
}

See also this Fiddle.

Answer 4

Function I wrote for a requirement similar to this with pure javascript string manipulation

"http://www.google.lk/?Name=John&Age=20&Gender=Male"

function queryize(sampleurl){
    var tokens = url.split('?')[1].split('&');
    var result = {};

    for(var i=0; i<tokens.length; i++){
        result[tokens[i].split('=')[0]] = tokens[i].split('=')[1];
    }

    return result;
}

Usage:

queryize(window.location.href)['Name'] //returns John
queryize(window.location.href)['Age'] //returns 20
queryize(window.location.href)['Gender'] //returns Male

Answer 5

If you have the querystring on hand, use this:

 /**
 * @param qry the querystring
 * @param name name of parameter
 * @returns the parameter specified by name
 * @author eduardo.medeirospereira@gmail.com
 */

function getQueryStringParameter(qry,name){
    if(typeof qry !== undefined && qry !== ""){
        var keyValueArray = qry.split("&");
        for ( var i = 0; i < keyValueArray.length; i++) {
            if(keyValueArray[i].indexOf(name)>-1){
                return keyValueArray[i].split("=")[1];
            }
        }
    }
    return "";
}

Answer 6

Okay, since everyone is ignoring my actual question, heh, I'll post mine too! Here's what I have:

location.querystring = (function() {

    // The return is a collection of key/value pairs

    var queryStringDictionary = {};

    // Gets the query string, starts with '?'

    var querystring = unescape(location.search);

    // document.location.search is empty if no query string

    if (!querystring) {
        return {};
    }

    // Remove the '?' via substring(1)

    querystring = querystring.substring(1);

    // '&' seperates key/value pairs

    var pairs = querystring.split("&");

    // Load the key/values of the return collection

    for (var i = 0; i < pairs.length; i++) {
        var keyValuePair = pairs[i].split("=");
        queryStringDictionary[keyValuePair[0]] = keyValuePair[1];
    }

    // Return the key/value pairs concatenated

    queryStringDictionary.toString = function() {

        if (queryStringDictionary.length == 0) {
            return "";
        }

        var toString = "?";

        for (var key in queryStringDictionary) {
            toString += key + "=" + queryStringDictionary[key];
        }

        return toString;
    };

    // Return the key/value dictionary

    return queryStringDictionary;
})();

And the tests:

alert(window.location.querystring.toString());

for (var key in location.querystring) {
    alert(key + "=" + location.querystring[key]);
}

Mind you thought, JavaScript isn't my native tongue.

Anyway, I'm looking for a JavaScript library (e.g. jQuery, Prototype) that already has one written. :)