[AndrewGSW]

Try this

function addItemsToForm(){
    var txtBoxesO = document.getElementById('newTextBoxes').getElementsByTagName('input');
    for (var i=0, j=txtBoxesO.length; i < j;  i++){
        var newTxt = txtBoxesO[i].cloneNode(true);
        newTxt.id = '';                     // ids must be unique, so delete it
        newTxt.className = 'dispBlock';     // cloning loses the class name
        document.getElementById('addedItems').appendChild(newTxt);
    }
}