You can use ajax to update certain fragments of the page using the $.ajax or $.getJSON functions, these functions will call your server side code and retrieve a json block, the json data can then be populated
$.ajax({ url: "mydomain.com/url", type: "POST", dataType: "xml/html/script/json", data: $.param( $("Element or Expression") ), complete: function(data) { var tag = $('#idonpage'); tag.text(data.something.etc); }, success: function() { //called when successful }, error: function() { //called when there is an error }, });
or you can use the $.load function using the form $.load('someurl #id'), jQuery will parse the html from someurl looking for the id tag and this data can be used to populate somewhere on your page.
to call a function at given intervals use the javascript setInterval function for example calling a function every 2 seconds :-
setInterval(function() { do something... },2000);
use the document ready function before setting all if this up.
$(document).ready(function() { });
Hope this points you in the right direction.