为什么这个ajax调用会触发页面上的onclick事件

Question

这件奇怪的事情发生了。我有一个php函数的ajax调用。该调用触发页面上的onclick事件。即使update.php是空白文件，即没有正在执行的脚本，也会发生这种情况。有什么可以解释这种行为？

    $.ajax({
        url: "update_event.php",
        type: "POST",
        data: { nodeid: event_id, title: event_title, source: selected_source, channel_id: channel_id, channel_name: channel_name, channel_onclick: channel_onclick, event_site: event_site, event_url: event_url, site_onclick: site_onclick, start_date: start_date_string, start_time: start_time_string, end_date: end_date_string, end_time: end_time_string, notes: event_notes, user_id: pl_user_id },
        cache: false,
        async: false,
        success: function (response) {
            success_flag = 1;
            if (response != '') 
            {
                /* alert(response); */
            }
        },
        error: function (request, status, error) {
            alert ("status "+status+" error "+error+"responseText "+request.responseText);
        },
    });