// JavaScript Document
today=new Date(); 
jran=today.getTime(); 
function rnd() { 
ia=9301; 
ic=49297; 
im=233280; 
jran = (jran*ia+ic) % im; 
return jran/(im*1.0); 
}; 
function rand(number) { 
return Math.ceil(rnd()*number); 
}; 
document.write("<center>"); 
for(i=1;i<=1;i++) { 
myNum=(rand(13)); //改成你要随机显示的图片数； 
if(myNum == 1) document.write("<img src='imagesgeffan/jk_01.jpg'>"); //图片路径，可用http:// 
if(myNum == 2) document.write("<img src='imagesgeffan/jk_02.jpg'>");  
if(myNum == 3) document.write("<img src='imagesgeffan/jk_03.jpg'>");  
if(myNum == 4) document.write("<img src='imagesgeffan/jk_04.jpg'>"); 
if(myNum == 5) document.write("<img src='imagesgeffan/jk_05.jpg'>"); 
if(myNum == 6) document.write("<img src='imagesgeffan/jk_06.jpg'>"); 
if(myNum == 7) document.write("<img src='imagesgeffan/jk_07.jpg'>"); 
if(myNum == 8) document.write("<img src='imagesgeffan/jk_08.jpg'>"); 
if(myNum == 9) document.write("<img src='imagesgeffan/jk_09.jpg'>"); 
if(myNum == 10) document.write("<img src='imagesgeffan/jk_10.jpg'>"); 
if(myNum == 11) document.write("<img src='imagesgeffan/jk_11.jpg'>"); 
if(myNum == 12) document.write("<img src='imagesgeffan/jk_12.jpg'>"); 
if(myNum == 13) document.write("<img src='imagesgeffan/jk_13.jpg'>");  
else { 
document.write(); 
} 
}; 
document.write("</center>");