How to revert the readonly attribute on an input box?

I am able to set the readonly property for an input ui control. I need to make it read-write on a button click (on an event). I am unable to revert it back.
Can somebody help me on this? Please treat this as an urgent request. I think this a very primitive requirement and I think I am missing something here. Below is the sample code:

var obj = new AW.UI.Input;
obj.setId("myInput");
obj.setAttribute("disabled","true");
obj.getContent('box/text').setAttribute('readonly', 'readonly');
obj.setControlText("Some text");
document.write(obj);

var button1 = new AW.UI.Button;
button1.setControlSize(90);
button1.setControlText("Enable edit");

button1.onControlClicked = function(event){
obj.setAttribute("disabled",null);
obj.getContent('box/text').setAttribute('readonly','');
obj.refresh();
}
document.write(button1);

--thank you

try

obj.getContent('box/text').setAttribute('readonly', null);

Hi Bryn!
Thank you for the response. I am using 2.0.1 version of AW. I tried the above mentioned, but I am unsucessful in reverting the readonly attribute. Can you please let me know where I am going?

Can anyone please help me?

--thanks and regards

There is a bug in child html caching in AW controls. To make your code working you need to clear internal _innerHTML and _outerHTML properties -

button1.onControlClicked = function(event){
    obj.setAttribute("disabled",null);
    obj.getContent('box/text').setAttribute('readonly','');
    obj.getContent('box')._outerHTML = "";
    obj.getContent('box')._innerHTML = "";
    obj._outerHTML = "";
    obj._innerHTML = "";
    obj.refresh();
}

:-(

Thanks Alex. It's working