window._open=window.open; 
window.open=function(sURL,sName,sFeatures,bReplace){ 
  if(sName==undefined){sName="_blank"}; 
  if(sFeatures==undefined){sFeatures=""}; 
  if(bReplace==undefined){bReplace=false}; 
  var win=window._open(sURL,sName,sFeatures,bReplace); 
  if(!win){ 
    alert('天啦！你的機(jī)器上竟然有軟件攔截彈出窗口耶，好討厭哦，人家不來了啦！快去掉嘛~~555~'); 
    return false; 
  } 
  return true; 
}

window.open("a.html","a"); 
window.open("b.html","a","",true);