Query-string encoding of a Javascript Object

like this?

serialize = function(obj) {
  var str = [];
  for (var p in obj)
    if (obj.hasOwnProperty(p)) {
      str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
    }
  return str.join("&");
}

console.log(serialize({
  foo: "hi there",
  bar: "100%"
}));
// foo=hi%20there&bar=100%25

Edit: this one also converts recursive objects (using php "array" notation for the query string)

serialize = function(obj, prefix) {
  var str = [],
    p;
  for (p in obj) {
    if (obj.hasOwnProperty(p)) {
      var k = prefix ? prefix + "[" + p + "]" : p,
        v = obj[p];
      str.push((v !== null && typeof v === "object") ?
        serialize(v, k) :
        encodeURIComponent(k) + "=" + encodeURIComponent(v));
    }
  }
  return str.join("&");
}

console.log(serialize({
  foo: "hi there",
  bar: {
    blah: 123,
    quux: [1, 2, 3]
  }
}));
// foo=hi%20there&bar%5Bblah%5D=123&bar%5Bquux%5D%5B0%5D=1&bar%5Bquux%5D%5B1%5D=2&bar%5Bquux%5D%5B2%5D=3

Just use URLSearchParams This works in all current browsers

new URLSearchParams(object).toString()

jQuery has a function for this, jQuery.param(), if you're already using it you can use that: http://api.jquery.com/jquery.param/

example:

var params = { width:1680, height:1050 };
var str = jQuery.param( params );

str now contains width=1680&height=1050