// JavaScript Document
var txt = new Array();
txt[0]="../works/img/main.jpg";
txt[1]="../works/img/main01.jpg";
txt[2]="../works/img/main02.jpg";
txt[3]="../works/img/main03.jpg";

mmax = 4; //メッセージ行数
txtno = Math.floor(Math.random() * mmax);
document.write("<img src='"+txt[txtno]+"'>");