JavaScript setInterval 初始延迟一秒的解决方案

var div = document.querySelector('div');
			var num = 10;
			setInterval(function(){
				if(num==1){
					div.innerHTML = null;
					return fn1;
				}else{
					num--;
					div.innerHTML = '还剩'+num+'秒';
				}
			},1000);

var div = document.querySelector('div');
			var num = 11;
			function fn1(){
				if(num==1){
					div.innerHTML = null;
					return fn1;
				}else{
					num--;
					div.innerHTML = '还剩'+num+'秒';
				}
			}
			setInterval(fn1,1000);
			fn1();