Set a delay in a jQuery / Ajax function

// set your delay here, 2 seconds as an example...
var my_delay = 2000;

// call your ajax function when the document is ready...
$(function() {
    callAjax();
});

// function that processes your ajax calls...
function callAjax() {
    $.ajax({
        // ajax parameters here...
        // ...
        success: function() {
            setTimeout(callAjax, my_delay);
        }
    });
}