function random(){
var ramimage = new Array("/common/images/btm2_key1.jpg","/common/images/btm2_key2.jpg","/common/images/btm2_key3.jpg","/common/images/btm2_key4.jpg","/common/images/btm2_key5.jpg");
var dd = new Date();
var sec = dd.getSeconds()
var curimg = ramimage[sec % ramimage.length];
document.write("<img src=\"" + curimg + "\" alt=\"30秒でわかる広経大\" WIDTH=\"754\" HEIGHT=\"123\" />");
}
random();