var randam;
var imgs = 8;//画像の数
function randomImg(){
    var rImgs = imgs - 1;
    n = Math.round(Math.random()*rImgs) + 1;
    imgID = document.getElementById("img" + n);
    nameID = document.getElementById("name" + n);
    imgID.style.display = "block";
    nameID.style.display = "block";
}
if(window.onload){
    randam = window.onload;
}
window.onload = function(){
    if(randam){
    randam.call(null);
    }
    randomImg();
}

function plus(){
    n = n + 1;
    if(n > imgs){
        n = 1;
    }
    m = n - 1;
    if(n == 1){
        m = imgs;
    }
    
    module();
    
}
function minus(){
    n = n - 1;
    if(n == 0){
        n = imgs;
    }
    m = n + 1;
    if(n == imgs){
        m = 1;
    }
    
    module();
    
}
function module(){
    var cimg = document.getElementById("img" + n);
    var cdimg = document.getElementById("img" + m);
    var cname = document.getElementById("name" + n);
    var cdname = document.getElementById("name" + m);
    
    cimg.style.display = 'block';
    cdimg.style.display = 'none';
    cname.style.display = 'block';
    cdname.style.display = 'none';
}