<p><a class="copy btn">Copy Grid 1 to Grid 2</a></p>
<script>
$(function(){
    $(".copy").on("click", function() {
        var grid1 = FormUtil.getField("field1");
        var grid2 = FormUtil.getField("field2");

        $(grid1).find(".grid-row").each(function(){
            var json = $(this).find("textarea").val();

            //remove id
            var obj = JSON.parse(json);
            if (obj.id !== undefined) {
                delete obj.id;
                json = JSON.stringify(obj);
            }

            $(grid2).enterpriseformgrid("addRow", {result: json });
        });
    });
});
</script>