clone input to another field

Hello,

I have two inputs:
<input type="text" id="field1" value="">
<input type="text" id="field2" value="">

As I type into field1, I want it to simultaneously show up in field2.

how do I do that?

Thanks!

Tony

<script type="text/javascript">

window.onload= function(){
var field1= document.getElementById('field1');
var field2= document.getElementById('field2');

field1.onkeyup= function(){field2.value= field1.value}
}

</script>

thank you !