ajaxrequest1

// in your HTML:
    <form>
        <select name="staff"> onchange="cs50Info(this.value);">
            <option value ="">Select someone:</opntion>
            <option value="blumberg">Hannah Blumberg</option>
            <option value="bowden">Rob Bowden</option>
        </select>
    </form>

// in your JS file:
function CS50Info(name)
{
    // deal with the situation where nothing is chosen
    if (name == "")
        return;

    // create a new AJAX object
    var ajax = new XMLHttpRequest();

    // when the page is loaded, have a callback function pre-fill our div
    ajax.onreadystatechange = function() {
        if (ajax.readyState == 4 && ajax.status == 200)
            $('#infodiv').html(ajax.responseText);
        }
    };

    // open the requested file and transmit the data
    ajax.open("GET", name + '.html', true);
    ajax.send();
}