SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">

JavaScript

var options = {key1: "value1", key2: "value2"};

var keys = [];
for(var key in options) {
  if(options.hasOwnProperty(key)) { //to be safe
    keys.push(key);
  }
}

var keyString = keys.join(", ");
alert(keyString);