child_process.spawn生成的子进程如何象jquery的live那样重新注册事件?

var child_process= require('child_process');
var iconv = require('iconv-lite');
 
 
 var domain=['www.google.com'];
 
var ping=child_process.spawn("ping",domain);
 
var result=''; 
 ping.stdout.on("data",function(data){
     
 result+= iconv.decode(data, 'gbk');
    
     console.log("ping ..." +domain);
     
     
 
 });
 
 ping.on("close",function(code){
     
      console.log(code);
     
      if(result.indexOf("100% 丢失") > 0 ){
          ping=child_process.spawn("ping",domain);
          
      }else {
          
          console.log("google is alive ");
          
      }
     result='';
 });

stdout.on('data'只有第一次执行有结果,重新生成的ping如果想要继续输出要怎么写?