Fehler Konsole sagt nichts.
$("#uploadlinkhoverForm").on('submit',(function(e) {
e.preventDefault();
$.ajax({
url: "uploadHover.php",
type: "POST",
data: "update="+document.getElementById("update_id").value,
contentType: false,
cache: false,
processData:false,
success: function(data)
{
var...