Try this code. You can use $.get instead of $.ajax
$( "input.suggest-user" ).autocomplete({
source: function( request, response ) {
$.ajax({
dataType: "json",
type : 'Get',
url: 'yourURL',
success: function(data) {
$('input.suggest-user').removeClass('ui-autocomplete-loading');
// hide loading image
response( $.map( data, function(item) {
// your operation on data
}));
},
error: function(data) {
$('input.suggest-user').removeClass('ui-autocomplete-loading');
}
});
},
minLength: 3,
open: function() {},
close: function() {},
focus: function(event,ui) {},
select: function(event, ui) {}
});