How to update the value in one text box based on the value entered in another text box?

Question

How do I update the value in one text box (txtInterest%) based on the value entered/changed in another text box (txtAmt)?

Answer 1

This should work assuming txtAmt and txtInterest% are ids on your page:

$(function() {
    $('#txtAmt').change(function() {
       $('#txtInterest%').val(this.value);
    });
});

See jQuery's change event handler.