var blocked = false ;

try {
    /*window.open()方法接受4个参数window.open(要加载的url，窗口目标，一个特性字符串，表示新页面是否取代浏览器历史记录中当前加载页面的布尔值)*/
    /*窗口目标还可以是_self,_parent ,_top, _blank*/
    var wroxWin = window.open("http://www.baidu.com","_self");
    if(wroxWin == null){
        blocked = true;
    }
}catch(ex){
    blocked = true ;
}

if(blocked){
    alert("The popup was blocked");
}

/*使用超时调用模拟间歇调用*/
var num = 0;
var max = 10;

function incrementNumber(){
    num++;
    /*如果执行次数未达到max设定的值则另一次超时调用*/
    if(num<max){
        setTimeout(incrementNumber,500);
    }else{
        alert(‘Done‘);
    }
}

setTimeout(incrementNumber,500);