cloning method in jsp

I hope you realize that this is a Java forum and not a Javascript forum. Your question has nothing to do with JSP and/or servlets.

As for your issue, start looking into jQuery. It has wonderful methods to manipulate the DOM. To get you started, this is what it sort of would look like (untested):

Java Code:

var textbox = "<input type=\"text\" />";
var counter = 1;
$("#yes-button").click( function() {
   var $myTextbox = $(textbox);
   $myTextbox.attr('name', 'text' + counter);
   $("#myform-container").append($myTextbox);
   counter++;
});