Detecting data changes in forms using jQuery

Question

I\'m using ASP.NET 2.0 with a Master Page, and I was wondering if anyone knew of a way to detect when the fields within a certain

or fieldset<

Answer 1

I came up with this piece of code in CoffeeScript (not really field tested, yet):

• Add class 'change_warning' to forms that should be watched for changes.

• Add class 'change_allowed' to the save button.

change_warning.coffee:

window.ChangeWarning = {
    save: ->
        $(".change_warning").each (index,element) ->
            $(element).data('serialized', $(element).serialize())

    changed: (element) ->
        $(element).serialize() != $(element).data('serialized')

    changed_any: ->
        $.makeArray($(".change_warning").map (index,element) -> ChangeWarning.changed(element)).some (f)->f
        # AKA $(".change_warning").any (element) -> ChangeWarning.changed(element)
        # But jQuery collections do not know the any/some method, yet (nor are they arrays)

    change_allowed: ->
        ChangeWarning.change_allowed_flag = true

    beforeunload: ->
        unless ChangeWarning.change_allowed_flag or not ChangeWarning.changed_any()
            "You have unsaved changes"
}

$ ->
    ChangeWarning.save()
    $(".change_allowed").bind 'click', -> ChangeWarning.change_allowed()
    $(window).bind 'beforeunload',     -> ChangeWarning.beforeunload()