jQuery Ajax内容未加载

I just trying to load a simple html page with ajax.

$("h1").click(function() {
    $.ajax({
    type: 'POST',
    url: 'ajax.html',
    success: function(response) {
            $('#buttonGroups').html(response);
            alert('Load was performed.');
        }
    });
})

But I never get the alert..? What am I missing?

You are using the response as an HTML so you need tell that to jquery:

$("h1").click(function() {
    $.ajax({
    type: 'POST',
    url: 'ajax.html',
    dataType: "html",   // <====
    success: function(response) {
            $('#buttonGroups').html(response);
            alert('Load was performed.');
        }
});