javascript函数：function() {}()的实战案例理解

基础不牢，房塌屋倒。javascript如果没有把基础知识掌握牢固的话，可能在实践中遇见一些本来很简单的实现方式，却劳师动众的用各种组合封装函数来实现一个简单的功能。

function() {}()

    (function() {
        const now = new Date();
        const year = now.getFullYear();
        const month = now.getMonth()+1;
        const day = now.getDate();
        $("#nowDate").html(year+"年"+month+"月"+day+"日");
    })();

等同于

    //获取当天日期
    $(function () {
        const now = new Date();
        const year = now.getFullYear();
        const month = now.getMonth() + 1;
        const day = now.getDate();
        $("#nowDate").html(year + "年" + month + "月" + day + "日");
    });

function showTime()

    //获取当天日期
    function showTime() {
        const now = new Date();
        const year = now.getFullYear();
        const month = now.getMonth() + 1;
        const day = now.getDate();
        $("#nowDate").html(year + "年" + month + "月" + day + "日");
    }

    showTime();

等同于

    //获取当天日期
    var showTime = function () {
        const now = new Date();
        const year = now.getFullYear();
        const month = now.getMonth() + 1;
        const day = now.getDate();
        $("#nowDate").html(year + "年" + month + "月" + day + "日");
    }

    showTime();

Done！