Data to be displayed in Textbox

hi,
you can do that in textbox onblur event .
function in javascript
function copy(Box 1,Box2)
{
 
// var box1= document.getElementById(Box1).value;
// var box2 = document.getElementById(Box2).value;
// box2.value=box1;
//---------------------------------------------------
var box1= document.getElementById(Box1);
var box2 = document.getElementById(Box2);
box2.value=box1.value
 
}
 
in .cs page
under pageload() you can add attribute as
box1.Attributes.Add("onblur","copy('"+box1.ClientID+"','"+box2.ClientID+"')");
 
this event will fire every time focus comes out of textbox 'box1'