If you want to dynamically load content into your page chances are your going to need to do some sort of request to a server in the background. The simplest way of doing this is to use jQuery's ajax function.

Here's an example of a GET request and a POST request:

$.ajax({
    type: "POST", // Set the HTTP type to POST
    url: "/serviceurl.aspx", // URL of the service
    data: "{data: [{"Field1": 1}] }", // Data to be posted to the service
    processData: false, // If set to true the data will be processed and turned into a query string
    success: (function (result) {
        // Result of the service call
    }),
    error: (function (jqXHR, textStatus, errorThrown) {
        alert(errorThrown);
    })
});
 
$.ajax({
    type: "GET", // Set the HTTP type to GET
    url: "/serviceurl.aspx", // URL of the service
    dataType: "jsonp", // Set what type of data you want back
    success: (function (result) {
        // Function that will be called on success
    })
});