You can "traverse the DOM" from the "current" element in the event handler, up to a common parent, and back down to the "neighboring" element that you're looking for. For example:
$(function (e) {
$(".form-select").change(function (event) {
alert(this.value); //shows the Value of the selected Option
alert($(this).closest('tr').find('td.Rechnernummer a').text()); // shows the Hostname
// etc.
});
});
The use of .closest()
selects the first matching parent element (traversing "up" the DOM) and then .find()
selects a matching element within that element (traversing back "down" the DOM).