Codepen演示
var userSelection = document.getElementsByClassName('menu');for(var i = 0; i < userSelection.length; i++) { (function(index) { userSelection[index].addEventListener("click", function() { console.log("Clicked index: " + index); }) })(i);}如@torazaburo在评论中指出的,如果要支持的浏览器符合最新版本的Javascript ECMAscript 6(ES6),则可以使用以下代码。
var userSelection = document.getElementsByClassName('menu');for(let i = 0; i < userSelection.length; i++) { userSelection[i].addEventListener("click", function() { console.log("Clicked index: " + i); })}


