DEMO of onkeypress event

JavaScript

<script type='text/javascript'>
var t1 = document.getElementById('t1'); 
t1.onkeypress=function(){my_code()};

function my_code(){
var text_val = document.getElementById('t1').value; 
document.getElementById('t2').innerHTML=text_val; 
}
</script>

HTML

<input  type=text id=t1 name=text> <br>
(Type minimum two chars)<br><br> will be copied to below textarea. <br>
<textarea id=t2   name=my_text rows=4 cols=30></textarea>

getElementById

plus2net.com