Js Event Task Scrypt

$(document).ready(function () {
    $("#add").click(function () {
        var lastField = $("#buildyourform div:last");
        var intId = (lastField && lastField.length && lastField.data("idx") + 1) || 1;
        var fieldWrapper = $("<div class=\"fieldwrapper\" id=\"field" + intId + "\"/>");
        fieldWrapper.data("idx", intId);
        var findex = "<span class=\"span-number\">" + intId + "</span>";
        var fName = $("<span class=\"span-field\"><label for=\"inputSubject\">Subject</label><input type=\"text\" onkeypress=\"return /[a-z]/i.test(event.key)\" class=\"form-control field-subject\" id=\"inputSubject\"/><span>");
        var removeButton = $("<span class=\"span-btn\"><button id=\"btn-remove\" type=\"button\" class=\"remove btn btn-danger btn-secondary\">x</button><span id=\"hovertext\">remove</span></span>");
        removeButton.click(function () {
            $(this).parent().remove();
        });
        fieldWrapper.append(findex);
        fieldWrapper.append(fName);
        fieldWrapper.append(removeButton);
        $("#buildyourform").append(fieldWrapper);
    });
    $("#preview").click(function () {
        $("#yourform").remove();
        var fieldSet = $("<fieldset id=\"yourform\"><legend><span class=\"table-first-column\">#</span>Subject</legend></fieldset>");
        $("#buildyourform div").each(function () {
            var id = $(this).attr("id").replace("field", "");
            var label = $("<label for=\"" + id + "\"><span class=\"table-first-column\">" + id + "</span>" + $(this).find("input.form-control").first().val() + "</label>");
            var input = $(this).find("input.form-control").first().val();
            if (input.length > 0) {
                fieldSet.append(label);
            }
        });
        $("body").append(fieldSet);
    });
    $("#empty").click(function () {
        $("#yourform").remove();
        var fieldSet = $("<fieldset id=\"yourform\"><legend><span class=\"table-first-column\">#</span>Subject</legend></fieldset>");
        $("#buildyourform div").each(function () {
            var id = $(this).attr("id").replace("field", "");
            var label = $("<label for=\"" + id + "\"><span class=\"table-first-column\">" + id + "</span>" + $(this).find("input.form-control").first().val() + "</label>");
            var input = $(this).find("input.form-control").first().val();
            if (input.length == 0) {
                delete id;
            }
        });
    });
});