Iterate over a Javascript associative array in sorted order

you could even prototype it onto object:

Object.prototype.iterateSorted = function(worker)
{
    var keys = [];
    for (var key in this)
    {
        if (this.hasOwnProperty(key))
            keys.push(key);
    }
    keys.sort();

    for (var i = 0; i < keys.length; i++)
    {
        worker(this[ keys[i] ]);
    }
}

and the usage:

var myObj = { a:1, b:2 };
myObj.iterateSorted(function(value)
{
    alert(value);
} 

You can use the Object.keys built-in method:

var sorted_keys = Object.keys(a).sort()

(Note: this does not work in very old browsers not supporting EcmaScript5, notably IE6, 7 and 8. For detailed up-to-date statistics, see this table)

You cannot iterate over them directly, but you can find all the keys and then just sort them.

var a = new Array();
a['b'] = 1;
a['z'] = 1;
a['a'] = 1;    

function keys(obj)
{
    var keys = [];

    for(var key in obj)
    {
        if(obj.hasOwnProperty(key))
        {
            keys.push(key);
        }
    }

    return keys;
}

keys(a).sort(); // ["a", "b", "z"]

However there is no need to make the variable 'a' an array. You are really just using it as an object and should create it like this:

var a = {};
a["key"] = "value";