Question

How do I use beforeSend callback in $.getJSON(cross domain).

More specifically $.getJSON is call is to a YQL service
Like

select * from html where
url=”http://www.yahoo.com”

Answer 1

The only purpose of beforeSend is to get at the raw XHR object (normally for setting HTTP headers on it). You don’t need it for kicking off spinners and the like. This code here (from @petersendidit):

jQuery.ajax({
    url: url,
    dataType: "json",
    beforeSend: function(){
        $('.loading').show();
    }
});

Is better written like this:

$('.loading').show();
jQuery.ajax({
    url: url,
    dataType: "json"
});

Which means, unless you need any advanced options in jQuery.ajax, your original plan to use jQuery.getJSON is just fine. So you say you want to show a loading GIF, just do this and forget about beforeSend.

jQuery(".someSpinnerImage").show();
jQuery.getJSON("http://www.somedomain.com/someurl", function(data) {
    jQuery(".someSpinnerImage").hide();
    // Do something with data
}