案例：5秒之后自动跳转页面

<button>点击</button>
<div></div>

<script>
    var btn = document.querySelector('button');
    var div = document.querySelector('div');
    btn.addEventListener('click', function() {
        location.href = 'http://www.cnblogs.com/';
    });
    var timer = 5;
    setInterval(function() {
        if (timer == 0) {
            location.href = 'http://www.cnblogs.com/';
        } else {
            div.innerHTML = '您将在' + timer + '秒钟之后跳转到首页';
            timer--;
        }
    }, 1000);
</script>