// JavaScript Document
var lastDiv = "";
function showDiv(divName) {
    // hide last div
    if (lastDiv) {
        document.getElementById(lastDiv).className = "hiddenDiv";
    }
    //if value of the box is not nothing and an object with that name exists, then change the class
    if (divName && document.getElementById(divName)) {
        document.getElementById(divName).className = "visibleDiv";
        lastDiv = divName;
    }
}