function $(element){

  return document.getElementById(element);

}

function on(element,event_name,handler,use_capture){

  if(addEventListener){

      $(element).addEventListener(event_name,handler,use_capture);

    }

  else{

    $(element).attachEvent('on'+event_name,handler);

  }

}

​

on("outer","click",o_click_c,true);

on("middle","click",m_click_c,true);

on("inner","click",i_click_c,true);

​

on("outer","click",o_click_b,false);

on("middle","click",m_click_b,false);

on("inner","click",i_click_b,false);

​

​

​

function o_click_c(){

    console.log("outer_捕获");

    alert("outer_捕获");

}

function m_click_c(){

    console.log("middle_捕获");

    alert("middle_捕获");

}

function i_click_c(){

    console.log("inner_捕获");

    alert("inner_捕获");

}

function o_click_b(){

    console.log("outer_冒泡");

    alert("outer_冒泡");

}

function m_click_b(){

    console.log("middle_冒泡");

    alert("middle_冒泡");

}

function i_click_b(){

    console.log("inner_冒泡");

    alert("inner_冒泡");

}