js入门套路

作者: 杨小伟的世界 | 来源:发表于2017-09-15 10:15 被阅读0次

    基本数据类型

    js的基本类型相对较多,这里只列举了部分,更详细的文档可以参考

    Javascript标准库

    整数型

    var age = 18;
    console.log('age is %d', age);
    console.log('age is %d', age + 2);
    

    字符类型

    var name = 'xiaoming';
    console.log('name is %s', name);
    console.log('name is %s', name + ' zhang');
    

    布尔型

    var isAdult = false;
    
    if (age >= 18)
      isAdult = true;
    else
      isAdult = false;
    
    console.log('%s %s', name, isAdult?'is Adult':'isn\'t Adult');
    

    列表

    var myLikeColorsList = ['blue', 'green', 'black', 'white'];
    console.log("myLikeColorsList has %d colors", myLikeColorsList.length);
    console.log("\tFirst color is %s", myLikeColorsList[0]);
    // add one to the end
    myLikeColorsList.push('purple');
    // delete one at the beginning
    myLikeColorsList.splice(0,1);
    for (color in myLikeColorsList)
      console.log("I like %s", myLikeColorsList[color]);
    

    自定义对象

    var JsLessonInfo = {
      teacher: name,
      title: 'JavaScript编程入门',
      beginTime: '2018/8/8',
      endTime: '2018/9/4',
      Student: 417,
      lessionTarget: '帮助更多小白学习JavaScript',
      githubUrl: 'https://github.com/xugy0926/getting-started-with-javascript'
    };
    console.log(JsLessonInfo);
    JsLessonInfo.teacher = name + ' zhang';
    console.log("Teacher name: %s", JsLessonInfo.teacher);
    
    // syntax suguar
    var xiaoming = {
      name,
      age
    }
    console.log("%s is %d year's old", xiaoming.name, xiaoming.age);
    

    流程控制

    分支语句

    if (age >= 80)
      console.log("A god");
    else if (age >= 60)
      console.log("An elder");
    else if (age >= 40)
      console.log("A strong");
    else
      console.log("A child");
    

    switch分支

    switch(age)
    {
    case 0:
      console.log("new baby");
      break;
    case 18:
      console.log("grown up");
      break;
    default:
      console.log("living?")
    }
    

    for循环

    for (var i = 0; i < myLikeColorsList.length; i++)
      console.log(myLikeColorsList[i])
    

    while循环

    var i = 0;
    while (i < myLikeColorsList.length) {
      console.log(myLikeColorsList[i]);
      i++;
    }
    

    函数

    function sum_to(n)
    {
      var sum = 0;
      var i = 0;
      for (i = 0; i <= n; i++) {
        sum += i;
      }
      return sum;
    }
    
    console.log(sum(10));
    

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