javascripturlquery-stringstring-parsing

How do I parse a URL query parameters, in Javascript?

Possible Duplicate:
Use the get paramater of the url in javascript
How can I get query string values in JavaScript?

In Javascript, how can I get the parameters of a URL string (not the current URL)?

like:

www.domain.com/?v=123&p=hello

Can I get "v" and "p" in a JSON object?

Solution

  • 2.5 years after the question was asked you can safely use Array.forEach. As @ricosrealm suggests, decodeURIComponent was used in this function.

    function getJsonFromUrl(url) {
  if(!url) url = location.search;
  var query = url.substr(1);
  var result = {};
  query.split("&").forEach(function(part) {
    var item = part.split("=");
    result[item[0]] = decodeURIComponent(item[1]);
  });
  return result;
}

    actually it's not that simple, see the peer-review in the comments, especially:

    For further details, see MDN article and RFC 3986.

    Maybe this should go to codereview SE, but here is safer and regexp-free code:

    function getSearchOrHashBased(url) {
  if(!url) url = location.href;
  var question = url.indexOf("?");
  var hash = url.indexOf("#");
  if(hash==-1 && question==-1) return "";
  if(hash==-1) hash = url.length;
  return question==-1 || hash==question+1
    ? url.substring(hash)
    : url.substring(question+1, hash);
}

// use query = getSearchOrHashBased(location.href)
// or query = location.search.substring(1)
function getJsonFromUrl(query) {
  var result = {};
  query.split("&").forEach(function(part) {
    if(!part) return;
    part = part.replaceAll("+", " ");
    var eq = part.indexOf("=");
    var key = eq>-1 ? part.substring(0,eq) : part;
    var val = eq>-1 ? decodeURIComponent(part.substring(eq+1)) : "";
    var from = key.indexOf("[");
    if(from==-1) result[decodeURIComponent(key)] = val;
    else {
      var to = key.indexOf("]",from);
      var index = decodeURIComponent(key.substring(from+1,to));
      key = decodeURIComponent(key.substring(0,from));
      if(!result[key]) result[key] = [];
      if(!index) result[key].push(val);
      else result[key][index] = val;
    }
  });
  return result;
}

    This function can parse even URLs like

    var url = "foo%20e[]=a%20a&foo+e[%5Bx%5D]=b&foo e[]=c";
// {"foo e": ["a a",  "c",  "[x]":"b"]}

var obj = getJsonFromUrl(url)["foo e"];
for(var key in obj) { // Array.forEach would skip string keys here
  console.log(key,":",obj[key]);
}
/*
  0 : a a
  1 : c
  [x] : b
*/

    7 years after the question was asked the functionality was standardized as URLSearchParams and 4 more years after, the access can be further simplified by Proxy as explained in this answer, however that new one can not parse the sample url above.