防止重复操作.js

function debounce(dom, event, fn, timeout) {
    var timeout = timeout || 3; // 默认延迟3s内点击无效
    var timer = null;
    // cornor cases
    if (!dom || !event || !(event in dom) || typeof fn !== 'function') {
        return
    }

    dom.addEventListener(event, function () {
        var _this = this;
        
        clearTimeout(timer);
        timer = setTimeout(function () {
            fn.apply(_this)
        }, timeout)
    })
}