jQuery get values of checked checkboxes into array

DEMO: http://jsfiddle.net/PBhHK/

$(document).ready(function(){

    var searchIDs = $('input:checked').map(function(){

      return $(this).val();

    });
    console.log(searchIDs.get());

});

Just call get() and you'll have your array as it is written in the specs: http://api.jquery.com/map/

$(':checkbox').map(function() {
      return this.id;
    }).get().join();

Call .get() at the very end to turn the resulting jQuery object into a true array.

$("#merge_button").click(function(event){
    event.preventDefault();
    var searchIDs = $("#find-table input:checkbox:checked").map(function(){
      return $(this).val();
    }).get(); // <----
    console.log(searchIDs);
});

Per the documentation:

As the return value is a jQuery object, which contains an array, it's very common to call .get() on the result to work with a basic array.

You need to add .toArray() to the end of your .map() function

$("#merge_button").click(function(event){
    event.preventDefault();
    var searchIDs = $("#find-table input:checkbox:checked").map(function(){
        return $(this).val();
    }).toArray();
    console.log(searchIDs);
});

Demo: http://jsfiddle.net/sZQtL/