jquery autocomplete with php source & json issue - php

Question

I want to create jquery autocomplete and php, the problem is the data shown in each record of the autocomplete has two values, I managed to do this like this (without PHP),
$(function() {
var authors = [
{
label: "jQuery",
desc: "the write less, do more, JavaScript library"
},
{
label: "jQuery UI",
desc: "the official user interface library for jQuery"
},
{
label: "Sizzle JS",
desc: "a pure-JavaScript CSS selector engine"
}
];
$( "#authorname" ).autocomplete({
minLength: 0,
source: authors,
focus: function( event, ui ) {
$( "#authorname" ).val( ui.item.label );
return false;
},
select: function( event, ui ) {
$( "#authorname" ).val( ui.item.label );
return false;
}
})
.data( "autocomplete" )._renderItem = function( ul, item ) {
return $( "<li></li>" )
.data( "item.autocomplete", item )
.append( "<a>" + item.label + "<br>" + item.desc + "</a>" )
.appendTo( ul );
};
});
now I want to change the source to php page (change authors to "getauthors.php")
I don't know what to put inside "getauthors.php" in order to pass two things for label and desc.
I managed to pass one thing like this using json,
<?php
$json = array();
$json[]="test";
$json[]="test2";
$json[]="test3";
echo json_encode($json);
?>
which outputs like this,
you can see that the second thing is always undefined, how I can pass value to this in php using json (or any other way).
Thanks.

Answer 1

<?php
$json = array();
$json[] = array ("label"=>"test", "desc"=>"description");
...
echo json_encode($json);
?>