如何解决“ $ is undefined”

Question

"I'm upgrade jQuery1.12.4 to jQuery3.3.1"

Error: "$ is undefined"

currentAjaxRequest = $.ajax({
        type: "POST",
        url: lookupurl,
        data: $(document.frmasp).serialize(),
        success: function (data) {
            $("#TDSearchCriteria > *").remove();
            if (data.substring(0, 2) == "
") {
                data = data.substring(2, data.length);
            }
            $("#TDSearchCriteria").append($(data).find("#TDSearchCriteria").html());
            $("#Result > *").remove();
            $("#Result").append($(data).find("#Result").html());
            $("#PageNumber > *").remove();
            $("#PageNumber").append($(data).find("#PageNumber").html());
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            alert("Error: " + errorThrown);
        }
    });  

Answer 1

--- Try this
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script>
$.ajax({
        type: "POST",
        url: lookupurl,
        data: $(document.frmasp).serialize(),
        success: function (data) {
            $("#TDSearchCriteria > *").remove();
            if (data.substring(0, 2) == "
") {
                data = data.substring(2, data.length);
            }


       $("#TDSearchCriteria").append($(data).find("#TDSearchCriteria").html());
            $("#Result > *").remove();
            $("#Result").append($(data).find("#Result").html());
            $("#PageNumber > *").remove();
            $("#PageNumber").append($(data).find("#PageNumber").html());
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            alert("Error: " + errorThrown);
        }
    }); 
  </script>