POST a js::array in JSON, got “undefined:undefined”

Question

I have a javascript array in the frontend, and I want to post it to my Tomcat server.

I'm using this code but it's not working as

        console.log("preview list. postUsers()");
        console.log(Ext.getCmp("preview-container").getUsers());
        $.ajax({
            url: "url",
            type: "POST",
            data: Ext.getCmp("preview-container").getUsers(),
            dataType: "json",
            success: function(rst){
                switch (rst){
                case true:
                    alert("success");
                    break;
                case false:
                    alert("failed");
                    break;
                }
            },
        });

The object is like this:

preview list. postUsers() 
["18241", "44598", "46558"]

But the POST result is like this:

   undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&undefined=undefined&

Which is parsed like this:

undefined: undefined ...

Am I missing anything important?

Answer 1

Looks like you are missing the post request parameter name

console.log("preview list. postUsers()");
console.log(Ext.getCmp("preview-container").getUsers());
$.ajax({
    url: "url",
    type: "POST",
    //send the users using parameter `users`
    data: { users: Ext.getCmp("preview-container").getUsers()},
    dataType: "json",
    success: function(rst){
        switch (rst){
            case true:
                alert("success");
                break;
            case false:
                alert("failed");
                break;
        }
    },
});