Update of David's project to add new table rows

I have simulated the $.get() by sending jsfiddle's AJAX simulator the row I wish to receive back!

HTML

<!--WE'LL USE THIS AS YOUR FORM-->
<!--and populate it from template below-->
<form>
    <input type="text" name="newFieldName" value="David" />
    <button id="add">Add</button><br/>
    <table id="fieldContainer"></table>
</form>

<!--THIS IS A TEMPLATE FOR OUR TABLE ROW-->
<table id="templateNew" style="display:none;">
<tr style="background-color:#FFFFFF; padding:10px;">
<td align="left">
    <input name="fieldName4" value="david" id="checkBox4" type="checkbox" />
&nbsp;<b>david</b></td>
<td style="padding-right:10px;">
<select name="fieldType4" id="fieldType4" onchange="showParameters(4,this);">
<option value="">Select Field Type</option>
<option value="checkbox">Checkbox</option>
<option value="multipleCheckbox">Checkbox (Multiple)</option>
<option value="date">Date</option>
<option value="file">File</option>
<option value="hidden">Hidden</option>
<option value="password">Password</option>
<option value="radio">Radio</option>
<option value="select">Select</option>
<option value="selectYN">Select (y/n)</option>
<option value="selectStateUS">Select U.S. State</option>
<option value="selectCountry">Select Country</option>
<option value="text">Text</option>
<option value="textarea">TextArea</option>
</select>
</td>
<td style="padding:10px;">
<b>Require:</b>&nbsp;<select name="require4" id="require4">
<option value="no">No</option>
<option value="yes">Yes</option>
</select>
</td>
<td id="contentCel4" style="padding:10px;background-color:#FFFFFF;">
<select name="content4" id="content4">
<option value="" default="">Test For</option>
<option value="text-input">Empty Field</option>
<option value="creditcard">Credit Card</option>
<option value="email">Email</option>
<option value="number">Number</option>
</select>
</td>
<td><select name="sort4" id="sort4">
<option value="">Select Row</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
</td><td>
<select name="cellGroup4" id="cellGroup4"...

JavaScript

//INSTRUCTIONS...
//Add a new name. Duplicates should be stopped.

function addField(e) {
    var fieldsArray = $("#fieldContainer input[name^=fieldName]").map(function (i, input) {
        return input.value;   //value of tag
    }).get();
    var newFieldName = $("input[name=newFieldName]").val();
    if (newFieldName == "") {
        alert("Field Name Required");
        e.preventDefault();
        return false;
    }
    // make sure field name isn't already used:
    if (fieldsArray.indexOf(newFieldName) >= 0) {
        alert("Field Name: " + newFieldName + " already in use");
        $("input[name=newFieldName]").focus();
        e.preventDefault();
        return false;
    }
    var newRowNumber = fieldsArray.length + 1;
    //var url = 'addField.php';
    var data = {
        newRowNumber: newRowNumber,
        newFieldName: newFieldName
    };
    //jsfiddle AJAX simulator needs POST not GET
    //and html data to return back, simulated delay
    data.html = createRow(newRowNumber, newFieldName).wrap('<div>').parent().html();
    data.delay = 1;
    url = '/echo/html/'; //for simulator
    $.post(url, data, function (newRow) {
        $('#fieldContainer').append(newRow);
        alert("Row has been added");
    });
    e.preventDefault();
    return false;
}

function showParameters(num, element){ //onchange
    alert("OnChange[" + num + "]: " + elementID);
}

// THIS FUNCTION CREATES A ROW FROM TEMPLATE
var $rowsTemplate;
function createRow(r, n) {
    var $rowClone = $rowsTemplate.clone();
    $("input[name=fieldName4]", $rowClone)
        .attr("name", "fieldName" + r)
        .attr("id", "checkBox" + r)
        .val(n)
        .parents("tr")
        .find("b")
        .text(n.toLowerCase());
    return $rowClone;
}

$(document).ready(function(){
    $("button#add").on("click", addField);
    // THIS CODE SETS UP OUR DUMMY DATA USING TEMPLATE
    var rows = ["Alan", "Tom", "Pete"];
    var $table = $("#fieldContainer");
    $rowsTemplate =...