<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>高阶函数 - 惰性加载函数</title>
</head>
<body>
<div style="width: 100px; height: 100px; background: #f60;" id="div1"></div>
<script>
/**
* 根据作用域链内部会重写外部的addEvent变量(如果在1. 2.处, 在addEvent前加上var就不是惰性了)
*/
var addEvent = function(ele, type, handler) {
if (window.addEventListener) { // 标准
addEvent = function(ele, type, handler) { // 1.
ele.addEventListener(type, handler, false);
};
} else if (window.attachEvent) {
addEvent = function(ele, type, handler) { // 2.
ele.attachEvent(‘on‘ + type, handler);
};
};
addEvent(ele, type, handler);
};
var div = document.querySelector(‘#div1‘);
addEvent(div, ‘click‘, function() {
console.log(111);
});
addEvent(div, ‘click‘, function() {
console.log(222);
})
</script>
</body>
</html>
时间： 2024-08-12 17:01:41