js方法实现页面停留几秒

js中不存在自带的sleep方法，要想休眠需要自己定义个方法

直接调用函数sleep(500),表示页面停留0.5s后在执行下面的代码

function sleep(numberMillis) { 
    var now = new Date(); 
    var exitTime = now.getTime() + numberMillis; 
    while (true) { 
        now = new Date(); 
        if (now.getTime() > exitTime) 
        return; 
    } 
}

	sleep: function(numberMillis) {
		var now = new Date();
		var exitTime = now.getTime() + numberMillis;
		while (true) {
			now = new Date();
			if (now.getTime() > exitTime)
				return;
		}
	},