java script

java script是什么？让我们一起来了解一下吧！

java script是一种客户端脚本语言。它是作用在客户端浏览器里，并且不需要编译，可以很快的被浏览器自带的解析引擎运行。

java script有以下特点：

1. 语法与c、java相似，可以用任意文字编辑工具

2. 由浏览器的解析引擎运行

3. 以对象为基础

4. 是一种弱类型语言

java script有六种数据类型：string、boolean、null、number、undefined、object。

实战举例，具体步骤如下：

let big = document.querySelector('.big');
        let small = document.querySelector('.small');
        let NS = document.querySelector('.l');
        let WE = document.querySelector('.r');
        let box = document.querySelector('.box');
        let Box = document.querySelector('.Box');
 
 
        // 倒计时模块
        var longNum = 10;
        var shortNum = 3;
        big.addEventListener('click', function () {
            let inputNum = prompt('请输入你想设置的秒数:');
            longNum = inputNum == '' ? longNum : inputNum;
        })
        small.addEventListener('click', function () {
            let inputNum = prompt('请输入你想设置的秒数:');
            shortNum = inputNum == '' ? longNum : inputNum;
        })
        green();
        Green = setInterval(green, 1000);
 
        function green() {
            NS.children[2].className = 'green_s';
            point(Box);
            NS.children[2].innerHTML = longNum;
            WE.children[0].className = 'red_s';
            caveat(box);
            WE.children[0].innerHTML = longNum;
            if (longNum == -1) {
                clearInterval(Green);
                NS.children[2].className = 'green_end';
                del(Box);
                NS.children[2].innerHTML = '';
                WE.children[0].className = 'red_end';
                del(box);
                WE.children[0].innerHTML = '';
                longNum = 10;
                NS.children[1].className = 'yellow_s';
                WE.children[1].className = 'yellow_s';
                yellow();
                Yellow = setInterval(yellow, 1000);
                remind(box);
                remind(Box);
            }
            longNum--;
        }
 
        function yellow() {
            NS.children[1].innerHTML = shortNum;
            WE.children[1].innerHTML = shortNum;
            if (shortNum == -1) {
                del(box);
                del(Box);
                clearInterval(Yellow);
                NS.children[1].className = 'yellow_end';
                NS.children[1].innerHTML = '';
                WE.children[1].className = 'yellow_end';
                WE.children[1].innerHTML = '';
                shortNum = 3;
                NS.children[0].className = 'red_s';
                caveat(Box);
                WE.children[2].className = 'green_s';
                point(box);
                red();
                Red = setInterval(red, 1000);
            }
            shortNum--;
        }
 
        function red() {
            NS.children[0].innerHTML = longNum;
            WE.children[2].innerHTML = longNum;
            if (longNum == -1) {
                clearInterval(Red);
                NS.children[0].className = 'red_end';
                del(Box);
                NS.children[0].innerHTML = '';
                WE.children[2].className = 'green_end';
                del(box);
                WE.children[2].innerHTML = '';
                longNum = 10;
                NS.children[2].className = 'green_s';
                WE.children[2].className = 'green_end';
                green();
                Green = setInterval(green, 1000);
            }
            longNum--;
        }
 
        function caveat(concent) {
            concent.style.color = 'red';
            concent.innerHTML = '闯红灯,等着大家都去你家吃席';
        }
 
        function remind(concent) {
            concent.style.color = 'yellow';
            concent.innerHTML = '黄灯了,还没过去的抓紧时间,马上车就来撞你了';
        }
 
        function point(concent) {
            concent.style.color = 'green';
            concent.innerHTML = '绿灯也要注意安全哟!';
        }
 
        function del(concent) {
            concent.innerHTML = '';
        }

以上就是小编今天的分享了，希望可以帮助到大家。