setInterval(f,1000); 　　　　　　设置计时器

clearInterval(screen_time);  　　清除计时器

<div class="cg_content">

<div class="success">

<img src="images/success.png">

<span>恭喜您 注册成功！</span>

</div>

<p>页面将在 <b>5</b> 秒内自动跳转到<a href="javascript:void(0)" οnclick="tiger();"> 微信首页</a></p>

</div>

<div class="zc_footer"></div>

<script type="text/javascript" src="jquery-1.11.1.min.js"></script>

<script type="text/javascript">

$(document).ready(function(){

var i = 5;

var f = function(){

i--;

$(".cg_content p b").text(i);

if(i == 0){

clearInterval(screen_time);

window.location='http://www.baidu.com';

}

// alert(screen_time);

}

var screen_time = setInterval(f,1000);

});

</script>

<script type="text/javascript">

function tiger(){

window.location='http://www.sina.com';

}

</script>