Q:

i want to use addEvent instead of onkeyup in html

<td valign="top"><center>
<textarea id="ta_in" rows="7" cols="42" onkeyup="get_ml()"></textarea><br>
<textarea id="ta_out" rows=7" cols="42"></textarea></center>
</td>

//javascript file.
function get_ml()
{
en  = "|" + document.getElementById("ta_in").value;
ml = "";
n = 0;
.....
.....
.....
document.getElementById("ta_out").value = ml;
}

//i need to use addEvent instead of onkeyup

A:

For modern browser compatibility, you would use addEventListener like this:
document.getElementById("ta_in").addEventListener("keyup", function(e) {
    var en  = "|" + document.getElementById("ta_in").value;
    var ml = "";
    var n = 0;
    .....
    .....
    .....
    document.getElementById("ta_out").value = ml;
});

Working demo: http://jsfiddle.net/jfriend00/6QMFV/
You would just run this code after your page has been loaded, by either placing the code at the end of your page (just before </body>) or by putting it in a function that you call from just before </body> or by calling this code for an event handler that listens for an event that tells you the page is loaded.

