document.getElementById("navMenu").innerHTML =
'<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">'+
    '<ul class="nav navbar-nav">'+
        '<li class="dropdown">'+
            '<a class="dropdown-toggle" data-toggle="dropdown" href="About.html">About Us' + '<span class="caret">' + '</span>'+ '</a>' +
    '<ul class="dropdown-menu">' +
    '<li>' + '<a href="E-Board.html">Executive Board</a>'+ '</li>' +
    '<li>' + '<a href="E-Board.html">' + 'Executive Board</a>'+ '</li>' +
    '</ul>' + '</li>' +
        '<li>'+
            '<a href="Membership.html">Membership</a>'+
        '</li>'+
        '<li>'+
            '<a href="Events.html">Events</a>'+
        '</li>'+
        '<li>'+
            '<a href="AIMSLab.html">AIMS Lab</a>'+
        '</li>'+
        '<li>'+
            '<a href="Contact.html">Contact</a>'+
        '</li>'+
    '</ul>'+
'</div>';

document.getElementById("navMenu").innerHTML =
'<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">'+
    '<ul class="nav navbar-nav">'+
        '<li class="dropdown">'+
            '<a class="dropdown-toggle" data-toggle="dropdown" href="About.html">About Us' + '<span class="caret">' + '</span>'+ '</a>' +
    '<ul class="dropdown-menu">' +
    '<li>' + '<a href="E-Board.html">Executive Board</a>'+ '</li>' +
    '</ul>' + '</li>' +
        '<li>'+
            '<a href="Membership.html">Membership</a>'+
        '</li>'+
        '<li>'+
            '<a href="Events.html">Events</a>'+
        '</li>'+
        '<li>'+
            '<a href="Lab.html">AIMS Lab</a>'+
        '</li>'+
        '<li>'+
            '<a href="Contact.html">Contact</a>'+
        '</li>'+
    '</ul>'+
'</div>';

Update nav.js