Q:

how do I create an array in jquery?

$(document).ready(function() {
  $("a").click(function() {
    $("#results").load("jquery-routing.php", 
       { pageNo: $(this).text(), sortBy: $("#sortBy").val()} 
    );
    return false;
  });
}); 

How do I create an array in jQuery and use that array instead of { pageNo: $(this).text(), sortBy: $("#sortBy").val()}

A:

Some thoughts:

jQuery is a JavaScript library, not a language. So, JavaScript arrays look something like this:
var someNumbers = [1, 2, 3, 4, 5];

{ pageNo: $(this).text(), sortBy: $("#sortBy").val()} is a map of key to value. If you want an array of the keys or values, you can do something like this:
var keys = [];
var values = [];

var object = { pageNo: $(this).text(), sortBy: $("#sortBy").val()};
$.each(object, function(key, value) {
    keys.push(key);
    values.push(value);
});

objects in JavaScript are incredibly flexible. If you want to create an object {foo: 1}, all of the following work:
var obj = {foo: 1};

var obj = {};
obj['foo'] = 1;

var obj = {};
obj.foo = 1;

To wrap up, do you want this?
var data = {};
// either way of changing data will work:
data.pageNo = $(this).text();
data['sortBy'] = $("#sortBy").val();

$("#results").load("jquery-routing.php", data);

A:

You may be confusing Javascript arrays with PHP arrays. In PHP, arrays are very flexible. They can either be numerically indexed or associative, or even mixed.
array('Item 1', 'Item 2', 'Items 3')  // numerically indexed array
array('first' => 'Item 1', 'second' => 'Item 2')  // associative array
array('first' => 'Item 1', 'Item 2', 'third' => 'Item 3')

Other languages consider these two to be different things, Javascript being among them. An array in Javascript is always numerically indexed:
['Item 1', 'Item 2', 'Item 3']  // array (numerically indexed)

An "associative array", also called Hash or Map, technically an Object in Javascript*, works like this:
{ first : 'Item 1', second : 'Item 2' }  // object (a.k.a. "associative array")

They're not interchangeable. If you need "array keys", you need to use an object. If you don't, you make an array.

* Technically everything is an Object in Javascript, please put that aside for this argument. ;)

A:

Not completely clear what you mean.  Perhaps:
<script type="text/javascript"> 
$(document).ready(function() {
  $("a").click(function() {
    var params = {};
    params['pageNo'] = $(this).text();
    params['sortBy'] = $("#sortBy").val();
    $("#results").load( "jquery-routing.php", params );
    return false;
  });
}); 
</script>

