[javascript] How to get all of the IDs with jQuery?

I am trying to gather a list (array) of ids in a sector

<div id="mydiv">
 <span id='span1'>
 <span id='span2'>
</div>

$("#mydiv").find("span"); 

gives me a jQuery object, but not a real array;

I can do

var array = jQuery.makeArray($("#mydiv").find("span"));

and then use a for loop to put the id attributes into another array

or I can do

$("#mydiv").find("span").each(function(){}); //but i cannot really get the id and assign it to an array that is not with in the scope?(or can I)

Anyhow, I just wanna see if there is a shorthand in jQuery to do that;

HTML

<div id="mydiv">
 <span id='span1'>
 <span id='span2'>
</div>

JQuery

var IDs = [];
$("#mydiv").find("span").each(function(){ IDs.push($(this).attr("id")); });

It's a late answer but now there is an easy way. Current version of jquery lets you search if attribute exists. For example

$('[id]')

will give you all the elements if they have id. If you want all spans with id starting with span you can use

$('span[id^="span"]')

The .get() method will return an array from a jQuery object. In addition you can use .map to project to something before calling get()

var idarray = $("#myDiv")
             .find("span") //Find the spans
             .map(function() { return this.id; }) //Project Ids
             .get(); //ToArray

My suggestion?

var arr = $.map($("#mydiv [id]"), function(n, i) {
  return n.id;
});

you could also do this as:

var arr = $.map($("#mydiv span"), function(n, i) {

or

var arr = $.map($("#mydiv span[id]"), function(n, i) {

or even just:

var arr = $("#mydiv [id]").map(function() {
  return this.id;
});

Lots of ways basically.

for(i=1;i<13;i++)     
{

   alert($("#tdt"+i).val());  

}  

Not a real array, but objs are all associative arrays in javascript.

I chose not to use a real array with [] and [].push because technically, you can have multiple ID's on a page even though that is incorrect to do so. So just another option in case some html has duplicated ID's

$(function() {

       var oArr = {};
       $("*[id]").each(function() {
           var id = $(this).attr('id');
           if (!oArr[id]) oArr[id] = true;
       });

       for (var prop in oArr)
           alert(prop);

   });

The best way I can think of to answer this is to make a custom jquery plugin to do this:

jQuery.fn.getIdArray = function() {
  var ret = [];
  $('[id]', this).each(function() {
    ret.push(this.id);
  });
  return ret;
};

Then do something like

var array = $("#mydiv").getIdArray();

You can get the ids of specifict tags and send it to a annother element. For exemple:

$("input").map(function() {
    $( "textarea" ).append(this.id+"\n");
});

It will get all input ids and send it to textarea.