myImageCnt = 4;
myImage = new Array(
"http://smallworld.west-tokyo.com/images/light_ball.jpg","http://smallworld.west-tokyo.com/images/grape.jpg","http://smallworld.west-tokyo.com/images/fruit_park.jpg","http://smallworld.west-tokyo.com/images/old_football_game.jpg"
);
myAlt = new Array(
"八ヶ岳自然ヒュッテのフットライト","ぶどう狩り","笛吹川フルーツ公園","サッカーゲーム"
);
myRnd = Math.floor(Math.random()*myImageCnt);
document.write("<img src='",myImage[myRnd],"' alt='",myAlt[myRnd],"' width='960' height='300' />");