how can i set readOnly textbox by using javascript?

Hi, 
Textbox have readonly property.

So , I want to set textbox by below code. textbox value is changed but not changed in cs code.
TextBox2.disabled = false; TextBox2.readOnly = false; TextBox2.value = "aaaa";
//TextBox2.Attributes.Add("readonly", "readonly"); is it possible to change readonly textbox value  by using javascript?