Additionally, if you would like to have a 'Select All' button, then it just has the same workflow as deselecting the options. Just add this below the first code in your HTML block. <a href="#" onclick="allSelected();">Select All</a>   Then, insert this in your Footer as well. <script> function allSelected(){     var elements = document.getElementById("InsertRecordFIELDNAME").options;     for(var i = 0; i < elements.length; i++){       elements[i].selected