function image_change(){
// ランダムに画像を表示する
jmp = new Array();
img = new Array();
// ジャンプ先のアドレス(数字は画像と対応)
jmp[0] = "./work/reform/7.html";
jmp[1] = "./work/reform/6.html";
jmp[2] = "./work/reform/11.html";
jmp[3] = "./work/culture/1.html";
jmp[4] = "./work/culture/2.html";
jmp[5] = "./work/building/1.html";
jmp[6] = "./work/station/3.html";
jmp[7] = "./work/commerce/2.html";
jmp[8] = "./work/reform/1.html";
jmp[9] = "./work/commerce/10.html";
jmp[10] = "./work/commerce/8.html";

// 画像のアドレス(数字はジャンプ先のアドレスと対応)
img[0] = "./image/work_top/1.gif";
img[1] = "./image/work_top/2.gif";
img[2] = "./image/work_top/3.gif";
img[3] = "./image/work_top/4.gif";
img[4] = "./image/work_top/5.gif";
img[5] = "./image/work_top/6.gif";
img[6] = "./image/work_top/7.gif";
img[7] = "./image/work_top/8.gif";
img[8] = "./image/work_top/9.gif";
img[9] = "./image/work_top/10.gif";
img[10] = "./image/work_top/11.gif";
n = Math.floor(Math.random()*jmp.length);
document.write("<a href='"+jmp[n]+"'>");
document.write("<img src='"+img[n]+"' border='0'>");
document.write("</a>");
}