<script type="text/javascript">
var num=0;
function numCount(){
document.getElementById('txt').value=num;
num=num+1;
setTimeout("numCount()",1000);
}
</script>

函數(shù)運(yùn)行思路，1.第二個(gè)setTimeout調(diào)用numCount函數(shù)? 2.numCount函數(shù)中的setTimeout又調(diào)用numCount，周而復(fù)始反復(fù)調(diào)用下去！

用一個(gè)函數(shù)來(lái)封裝一下：

function example(){
//其他語(yǔ)句;
 ? ? ? ?setTimeout("example()",1000);
}
setTimeout("example()",1000);