Question

Is there any reason why I shouldn’t do something like the following (to avoid using a hidden field to store the temporary information)? I’m using jQuery syntax for brevity but it’s a general JavaScript question.

function editComments() {
    window.currentComments = $('#commentsTextBox').val();
    $('#commentsTextBox').removeAttr("readonly");
}

function cancelEditComments() {
    $('#commentsTextBox').val(window.currentComments);
    $('#commentsTextBox').attr("readonly", "readonly");
}

I know that globals are generally considered bad practice, but is there really any problem with doing the above?

Please don’t answer/comment with “globals variables are evil” unless you can give a reason/explanation.

Answer 1

There’s no real problem with this except that global variables are evil. 😉

However, if you are using jQuery anyway, in my opinion, a much nicer way is to store it in the element using data():

function editComments() {
    $('#commentsTextBox').data("oldValue", $('#commentsTextBox').val());
    $('#commentsTextBox').removeAttr("readonly", "readonly");
}

function cancelEditComments() {
var oldValue = $('#commentsTextBox').data("oldValue");
$('#commentsTextBox').val(oldValue );
$('#commentsTextBox').attr("readonly", "readonly");
}

As long as you keep it inside the script, and nothing else gets done with the element, that should work fine.