function switchTOC(toc_new){
    // turn off all table of contents divs
    document.getElementById('entrees').style.display = 'none';
    document.getElementById('sandwiches').style.display = 'none';
    document.getElementById('salads_sides_sauces').style.display = 'none';
    document.getElementById('school_egg').style.display = 'none';
    document.getElementById('school_chicken').style.display = 'none';
    if (document.getElementById('breakfast_sandwiches')) document.getElementById('breakfast_sandwiches').style.display = 'none';
    
    // turn on the new table of contents
    document.getElementById(toc_new).style.display = 'block';
}

function revisit(){
    var locate = window.location.toString().split('=')[1];
    if (locate != null){
        switchTOC(locate);
    }
}