javascript（小试牛刀）实现图片循环切换功能

代码如下

var nnn;

nnn=1;

imgchange();

function imgchange()

{

if(nnn==1)

{ document.getElementById('focuspic1').style.display="block";

document.getElementById('focuspic2').style.display="none";

document.getElementById('focuspic3').style.display="none";

document.getElementById('focusnum1').style.color="yellow";

document.getElementById('focusnum2').style.color="black";

document.getElementById('focusnum3').style.color="black";

setTimeout('imgchange()',1000);

}

if(nnn==2)

{ document.getElementById('focuspic1').style.display="none";

document.getElementById('focuspic2').style.display="block";

document.getElementById('focuspic3').style.display="none";

document.getElementById('focusnum1').style.color="black";

document.getElementById('focusnum2').style.color="yellow";

document.getElementById('focusnum3').style.color="black";

setTimeout('imgchange()',1000);

}

if(nnn==3)

{ document.getElementById('focuspic1').style.display="none";

document.getElementById('focuspic2').style.display="none";

document.getElementById('focuspic3').style.display="block";

document.getElementById('focusnum1').style.color="black";

document.getElementById('focusnum2').style.color="black";

document.getElementById('focusnum3').style.color="yellow";

setTimeout('imgchange()',1000);

}

nnn++;

if(nnn==4)

{

nnn=1;

}

}