QUERY_STRING をパースする JavaScript 関数。今まで何度も書いたと思うけど！

parse_query_param.js

/**
 * @example
 * 
 * var param1 = parse_query_param(location.search.substr(1));
 * 
 * var param2 = parse_query_param(location.hash.search(/^#!.*\?/)?"":location.hash.replace(/^#!.*\?/, ""))
 */

function parse_query_param(query) {
  var vars = query.split(/[&;]/);
  var param = {};
  for (var i = 0; i < vars.length; i++) {
    var pair = vars[i];
    if (!pair.length) continue;
    var pos = pair.indexOf("=");
    var key, val;
    if (pos > -1) {
      key = pair.substring(0, pos);
      val = pair.substring(pos + 1);
    } else {
      key = val = pair;
    }
    key = key.replace(/\+/g, " ");
    val = val.replace(/\+/g, " ");
    key = decodeURIComponent(key);
    val = decodeURIComponent(val);
    param[key] = val;
  }
  return param;
}