Javascript基础

Posted 2020-08-24 iwideal

1、字符串操作

var str = "abaasdffggghhjjkkgfddsssss3444343";

function strFun() {
    //获取字符串长度
    var a = str.length;
    console.log(a);
    //获取指定位置的字符
    var b = str.charAt(32);
    console.log(b);
    //获取字母“i”第一次出现的位置，如果没有，返回-1
    var c = str.indexOf(‘i‘);
    if (c < 0) {
        console.log(‘不存在‘);
    } else {
        console.log(c);
    }
    //将aa替换成bb
    var d = str.replace(‘aa‘, ‘bb‘);
    console.log(str);
    console.log(d);
    //截取字符串
    var e = str.substring(1, 5);
    console.log(e);
    //分割字符串，返回数组
    var g = str.split(‘‘);
    //对数组进行排序
    var f = g.sort();
    var arr = new Array(str.length);
    for (var i = 0; i < f.length; i++) {
        var number = 1;
        for (var j = 1; j < f.length; j++) {
            if (f[i] == f[j]) {
                number = number + 1;
            }
        }
        console.log(‘字母‘ + f[i] + ‘出现了：‘ + number + ‘次‘);
    }
    //向数组的尾部插入元素
    g.push(‘@‘);
    //向数组的头部插入元素
    g.unshift(‘@‘);
    //数组转化成字符串
    var h = g.join(‘‘);
    console.log(h);

}
strFun();

 2、时间日期

function curDateTime() {
    //获取年月日
    var d = new Date();
    var year = d.getFullYear();
    var month = d.getMonth() + 1;
    var date = d.getDate();
    console.log(year + ‘年‘ + month + ‘月‘ + date + ‘日‘);
    //获取时分秒
    var hour = d.getHours();
    var minute = d.getMinutes();
    var second = d.getSeconds();
    console.log(hour + ‘:‘ + minute + ‘:‘ + second);
    console.log(year + ‘年‘ + month + ‘月‘ + date + ‘日‘ + hour + ‘:‘ + minute + ‘:‘ + second);
    //获取一个星期内的第几天
    var day = d.getDay();
    var arr = [‘星期天‘, ‘星期一‘, ‘星期二‘, ‘星期三‘, ‘星期四‘, ‘星期五‘, ‘星期六‘];
    var weekDay = arr[day];
    console.log(year + ‘年‘ + month + ‘月‘ + date + ‘日‘ + hour + ‘:‘ + minute + ‘:‘ + second + weekDay);
}
curDateTime();