Disable ASP:dropdownlist based on the selection of another ASP:Dropdownlist.value

Question

I have two asp.net dropdownlists that I want to manipulate clientside with Javascript. These two dropdowns are inside a modal open: function()

When dropdown1.value == "me" I want dropdown2.value to be disabled

How can I accomplish this?

$(document).ready(function () {
                    if (document.getElementById('<%=dropdown1.ClientID%>').value == 'Me')
                        document.getElementById('<%=dropdown2.ClientID%>').disabled = true;
                    });

(optional) Part 2 I need to set an entity framework value to null after dropdown2 has been disabled how could I accomplish this without a postback?

Answer 1

Part 1:

$(document).ready(function () 
{
   if($("#<%=dropdown1.ClientID%>").val() == "Me")
      $("#<%=dropdown2.ClientID%>").prop("disabled",true);
});

Part 2 :

You would need to make an ajax call to a code behind or webservice to do that.

.ASPX

$.ajax({
                type: "POST",
                url: "PageName.aspx/CodeBehindMethodName",
                data: "{}",
                contentType: "application/json; charset=utf-8",
                dataType: "json",

            success: function (result) {


            },
            error: function (error) {

            }
             });

.ASPX.CS

 [WebMethod]
        public static void Test()
        {
          // Call EF code
        }