<script language="JavaScript">
<!--
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(10)); //改成你要随机显示的图片数；
    if(myNum == 1) document.write("<img src='imgs/step.gif'>");
if(myNum == 2) document.write("<img src='imgs/step1.gif'>"); //图片路径，可用http://
if(myNum == 3) document.write("<img src='imgs/step2.gif'>");
if(myNum == 4) document.write("<img src='imgs/step3.gif'>");
if(myNum == 5) document.write("<img src='imgs/step4.gif'>");
if(myNum == 6) document.write("<img src='imgs/step5.gif'>");
if(myNum == 7) document.write("<img src='imgs/step6.gif'>");
if(myNum == 8) document.write("<img src='imgs/step7.gif'>");
if(myNum == 9) document.write("<img src='imgs/step1.gif'>");
if(myNum == 10) document.write("<img src='imgs/step2.gif'>");
    else {
document.write();
}

};

document.write("</CENTER>");

</script>