点击按钮后每隔一秒计数器增加1，通过setTimeout实现
<!DOCTYPE html>
<html>
<head>
<script>
var c=0;
var t;
var timer_is_on=0;
function timedCount()
{
document.getElementById('txt').value=c;
c=c+1;
t=setTimeout("timedCount()",1000);
}
function doTimer()
{
if (!timer_is_on)
{
timer_is_on=1;
timedCount();
}
}
</script>
</head>
<body>
<form>
<input type="button" value="Start count!" onClick="doTimer()">
<input type="text" id="txt">
</form>
<p>Click on the button above. The input field will count forever, starting at 0.</p>
</body>
</html>
开心洋葱 , 版权所有丨如未注明 , 均为原创丨未经授权请勿修改 , 转载请注明JavaScript如何使用setTimeout实现一个计时器！
