Adding & Deleting Table Rows

Adds a table row to the bottom on click with "Add Button". Deletes only checked Items with the click of "Delete Button"

HTML

<script src="http://tablesorter.com/__jquery.tablesorter.min.js"></script>
    <table id="box-table-a">
    
        <!-- Table header -->
            <thead>
                <tr>
                    <th scope="col" ><a href='#' id='selectAll'>Select</a></th>
                    <th scope="col" >Name</th>
                    <th scope="col" >Units</th>
                    <th scope="col" >Calories</th>
                    <th scope="col" >Sugar</th>
                </tr>
            </thead>
        
        <!-- Table body -->
            <tbody  style="overflow: hidden; height: 25px; width: 320px;">
                <tr class='normal' id='hidden'>
                    <td><input type="checkbox" /></td>
                    <td><select>
                        <option>Select an item:</option>
                        <option>Food</option>
                        <option>Water</option>
                        </select></td>
                    <td>1</td>
                    <td>2</td>
                    <td>3</td>
                </tr>
                <tr class="normal" id="0">
                    <td><input type="checkbox" /></td>
                    <td><select>
                        <option>Select an item:</option>
                        <option>Food</option>
                        <option>Water</option>
                        </select></td>
                    <td>1</td>
                    <td>2</td>
                    <td>3</td>
                </tr>
                <tr class="normal" id="1">
                    <td><input type="checkbox" /></td>
                    <td><select>
                        <option>Select an item:</option>
                        <option>Food</option>
                        <option>Water</option>
                        </select></td>
                    <td>4</td>
                    <td>5</td>
                    <td>6</td>
                </tr>
                </tbody>
                <tfoot>
                    <tr>
    ...

CSS

#box-table-a
{
    font-family: "Lucida Sans Unicode", "Lucida Grande", Sans-Serif;
    font-size: 12px;
    margin: 45px;
    width: 480px;
    text-align: left;
    border-collapse: collapse;
}
#box-table-a th
{
    font-size: 13px;
    font-weight: normal;
    padding: 8px;
    background: #b9c9fe;
    border-top: 4px solid #aabcfe;
    border-bottom: 1px solid #fff;
    color: #039;
      cursor: pointer;
}
#box-table-a td
{
    padding: 8px;
    
    border-bottom: 1px solid #fff;
   
    border-top: 1px solid transparent;
}
#box-table-a tr:hover td
{
    background: #d0dafd;
    color: #339;
    cursor: pointer;
}

.normal
{
    background: #e8edff; 
    color: #339;
     color: #669;
}

.highlight
{
     background: #d0dafd;
    color: #339;
}
.hidden
{
  visibility:hidden;
    display: none;
}

#box-table-a th.headerSortUp { 
    background-image: url(../img/small_asc.gif); 
    background-color: #3399FF; 
} 

#hidden
{
    display: none;
}

JavaScript

$(document).ready(function() {
    var rowCount = $('#box-table-a tbody>tr').length;
    var flag = 0;
    
    $("#box-table-a").tablesorter(); 
    
    //Click on tr highlights and checks checkbox
     $("#box-table-a tbody tr").click(function() {
        
        //Highlights the clicked row
         if($(this).hasClass("normal")){
            $(this).removeClass("normal").addClass("highlight");
        }
        else {
            $(this).removeClass("highlight").addClass("normal");                                    
        }     
        
        //Checks the checkbox
        var $target = $(event.target);
        if(!$target.is('input:checkbox')) {
            
            $(this).find('input:checkbox').each(function() {
                if(this.checked) { this.checked = false; }
                else { this.checked = true;}
            });
        }
    });//End tr click
    
    
    
    //Add Rows to table
    $('#addRows').click(function() {
       
        $('#box-table-a tbody>tr:first').clone(true).insertAfter('#box-table-a tbody>tr:last');
        
        $('#box-table-a tbody>tr:last').attr("id", "txtHint");
        $('#box-table-a tbody>tr:nth-child(rowCount -1').attr("id", "row"+rowCount);
          
         rowCount += 1;
        alert($('#box-table-a tbody>tr:last').attr('id'));
    });//End Add Rows
    
    //Delete Checked Rows 
    $('#delRows').click(function() {

         $('#box-table-a tbody>tr').each(function() {
                    
             if($(this).attr("id") !== "0") {
                 if($(this).find('input').attr('checked')) {
                       
                         rowCount = rowCount - 1;
                         if(rowCount !== 0) {
                               $(this).remove();
                            }
                 }
             }
              else {
                  idNum = $(this).attr("id");
                  alert("First Row Cannot Be Deleted!\n ID: "+idNum);
                 
            ...