正确使用addEventListener（）/ attachEvent（）？

Question

我不知道如何使用addEventListener分别attachEvent正确？window.onload = function (myFunc1) { /* do something */ }function myFunc2() { /* do something */ }if (window.addEventListener) {  window.addEventListener('load', myFunc2, false);} else if (window.attachEvent) {  window.attachEvent('onload', myFunc2);} // ...要么function myFunc1() { /* do something */ }if (window.addEventListener) {  window.addEventListener('load', myFunc1, false);} else if (window.attachEvent) {  window.attachEvent('onload', myFunc1);}function myFunc2() { /* do something */ }if (window.addEventListener) {  window.addEventListener('load', myFunc2, false);} else if (window.attachEvent) {  window.attachEvent('onload', myFunc2);} // ...？这个跨浏览器是安全的还是我应该更好地使用这样的东西：function myFunc1(){ /* do something */ }function myFunc2(){ /* do something */ }// ...function addOnloadEvent(fnc){  if ( typeof window.addEventListener != "undefined" )    window.addEventListener( "load", fnc, false );  else if ( typeof window.attachEvent != "undefined" ) {    window.attachEvent( "onload", fnc );  }  else {    if ( window.onload != null ) {      var oldOnload = window.onload;      window.onload = function ( e ) {        oldOnload( e );        window[fnc]();      };    }    else      window.onload = fnc;  }}addOnloadEvent(myFunc1);addOnloadEvent(myFunc2);// ...AND：myfunc2仅适用于IE 7。如何相应地修改正确/首选方法？