How it will implemented with wicket. 
When a single digit entered in second textfield automatically same changes appear in first textfield :
my code:

```
txtLtpPriceCE.add(new AjaxFormSubmitBehavior("onkeyup") {
        @Override
        protected void onSubmit(AjaxRequestTarget target) {
            System.out.println(txtLtpPriceCE.getInput());
            showCalculatorModel.setTxtIntrinsicValueCE(txtLtpPriceCE.getInput());
            target.addComponent(txtIntrinsicValueCE);
         }

         @Override
         protected void onError(AjaxRequestTarget target) {
             throw new UnsupportedOperationException("Not supported yet.");
         }
});

```

My component:

```
final TextField txtLtpPriceCE = new TextField("txtLtpPriceCE",
             new PropertyModel(showCalculatorModel, "txtLtpPriceCE"));
item.add(txtLtpPriceCE);

final TextField txtIntrinsicValueCE = new TextField("txtIntrinsicValueCE",
             new PropertyModel(showCalculatorModel, "txtIntrinsicValueCE"));
item.add(txtIntrinsicValueCE);
txtIntrinsicValueCE.setOutputMarkupId(true);

```