方式一:闭包
var elems = document.getElementsByTagName('a');
for (var i = 0; i < elems.length; i++) {
(function (lockedInIndex) {
elems[i].addEventListener('click', function (e) {
e.preventDefault();
alert('I am link #' + lockedInIndex);
}, 'false');
})(i);
}
方式二: let 方式
var elems = document.getElementsByTagName('a');
for (let i = 0; i < elems.length; i++) {
elems[i].addEventListener('click', function (e) {
e.preventDefault();
alert('I am link #' +i);
}, 'false');
}