常用的3秒钟跳到哪儿里

var i = 2;
var str= document.getElementById('msg').innerHTML;
	
//alert(str.indexOf('上传头像成功'));
	
if(document.getElementById('step3').style.display=='block' && str.indexOf('上传头像成功')>0 )
	{
		setTimeout("window.location='user_recommend.php'",3000);
		setInterval("time()",1000);
	}
	
	function time()
	{
		document.getElementById('time').innerHTML = i;
		if (i>0)
		{
			i--;
		}
	
		//alert(i);
	}