//run on page load
$(function(){
    //bind a click event to the nav links
    $("#nav a").bind("click", function(e){

        //keep the links from going to another page by preventing their default behavior
        e.preventDefault();

        //this = link; grab the url
        var pageLocation = this.href;

        //fire off an ajax request
        $.ajax({
            url: pageLocation,

        //passing data
        data: { foo: "bar", something: "else" },

        //defining transport method (it's GET by default anyway, but you could change to post or whatever's relevant)
        type: "GET",

            //on success, set the html to the responsetext
            success: function(data){
                $("#content").html(data.responseText);
            }
        });
    });
});