Add URL params to a page with pushState

add_url_params.js

// Simply pass in the params you want as an object, e.g. addURLParams({ foo: 'bar' })
var addURLParams = function(newParams) {
  if (!newParams || typeof(newParams) !== 'object') {
    return false;
  }
  
  var extend = function(out) {
    out = out || {};

    for (var i = 1; i < arguments.length; i++) {
      if (!arguments[i])
        continue;

      for (var key in arguments[i]) {
        if (arguments[i].hasOwnProperty(key))
          out[key] = arguments[i][key];
      }
    }

    return out;
  };
  
  var jsonify = function(string) {
    return JSON.parse(string.replace(/\?/, '{"').replace(/&/g, '","').replace(/=/g, '":"').replace(/$/, '"}'));
  }
  
  var search = window.location.search,
      params;
      
  if (search) {
    var oldParams = jsonify(search);
    params = extend({}, oldParams, newParams);
  } else {
    params = newParams;
  }
  
  var paramString = "?"
  for (var key in params) {
    if (params.hasOwnProperty(key)) {
      paramString += key + '=' + params[key] + '&';
    }
  }
  paramString = paramString.replace(/&$/, '');
  
  if (window.history && history.pushState) { 
    window.history.pushState(params, '', window.location.pathname + paramString);
  } else {
    window.location = window.location.pathname + paramString;
  }
}