<form name="form1" method="post" action="">
<input type="text" name="textfield" id="text1" onkeyup="aa(this)">
<input type="text" name="textfield" id="text2">
</form>
<script language="javascript">
function aa(obj){
document.getElementById("text2").value=obj.value
}
</script>
<input type="text" name="textfield" id="text1" onkeyup="aa(this)">
<input type="text" name="textfield" id="text2">
</form>
<script language="javascript">
function aa(obj){
document.getElementById("text2").value=obj.value
}
</script>
<input type="text" name="textfield" id="text1" onpropertychange="aa(this)">
<input type="text" name="textfield" id="text2">
</form>
<script language="javascript">
function aa(obj){
document.getElementById("text2").value=obj.value
}
</script>