var img = new Array;

img[0] = "./img/common/category_title.jpg";
img[1] = "./img/common/category_title02.jpg";
img[2] = "./img/common/category_title03.jpg";
img[3] = "./img/common/category_title04.jpg";
function random_img(){
        var i = myrandom(img.length) - 1;
        document.write("<IMG SRC=\""+img[i]+"\" />");
}
function myrandom(max){
        var v = max * Math.random();
        if(v == 0.0){v = 1;}else{v = Math.ceil(v);}
        return v;
}