Question

setInterval为什么只执行一次

<script language="javascript" type="text/javascript">
function olol(){
document.write("aaaa");

}

setInterval(olol,3000);
</script>

Answer 1

因为dom完全载入后..document.write是对整个dom进行了重写~~

<script type="text/javascript">
var i = 0;
function olol() {
++i;
document.write(i);
}

setInterval(olol, 3000);
</script>