Question

I have the following code which basically is a checkbox that causes a submit to take place.
As the task gets deleted for the DB, it is a requirement that some box comes up and says, “are you sure” or the likes, to confirm deletion.

<input type="checkbox" 
       onclick="location.href='@Url.Action("Complete", "Tasks", 
                                           new { TaskID = item.TaskID })'" />

This uses Razor syntax.

Answer 1

You could use the confirm method:

<input type="checkbox" onclick="if (confirm('Are you sure?')) { window.location.href = '@Url.Action("Complete", "Tasks", new { TaskID = item.TaskID })'; }" />

or in a more unobtrusive way with jquery:

<input type="checkbox" id="complete" name="complete" data-url="@Url.Action("Complete", "Tasks", new { TaskID = item.TaskID })" />

and then in a separate javascript file:

$(function() {
    $('#complete').click(function() {
        if (confirm('Are you sure?')) {
            window.location.href = $(this).data('url');
        }
    });
});

Also I would very strongly recommend you using another verb than GET on controller actions that modify state on your server such as marking a task as completed. PUT, POST and DELETE are good candidates. In your case since you are modifying an existing item the POST verb seems most natural.