<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <!--<style type="text/css"></style>--> <link rel="stylesheet" type="text/css" href="./css/index.css"> </head> <body> <!--一、外接式--> <!--<script type="text/javascript" src="./js/index.js"></script>--> <!--二、内接式--> <!-- 一、建议在body以后书写js代码 二、注意代码结尾的分号 --> <script type="text/javascript"> alert('cuixiaozhao'); console.log('崔晓昭'); </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <script type="text/javascript"> //js中的变量声明方式,使用var关键字,js是一个弱类型的语言; //一、变量的声明和定义 var a = 100; alert(a); //二、先声明变量,将来定义; var b; b = '200'; console.log(a); console.log(b); //c未定义,就使用,undefined; console.log(c); </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <!-- 一、js的基本数据类型: number string boolean null undefined --> <script type="text/javascript"> // var $ = 100; // console.log($); var a = 100; console.log(a); console.log(typeof a); var b = 26 / 0;//Infinity,表示无限大! console.log(typeof b); console.log(b); var c = '崔晓昭'; console.log(c); console.log(typeof c); var d = ""; console.log(d); console.log(typeof d); //JavaScript中的+多是连字符也多是加法符号,表示运算; console.log('cui' + 'xiaozhao'); console.log(1 + 2 + 3); var e = 11 + ''; console.log(e); console.log("E的数据类型为:", typeof e); </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <!-- 一、js的基本数据类型: number string boolean null undefined --> <script type="text/javascript"> // var $ = 100; // console.log($); //number var a = 100; console.log(a); console.log(typeof a); //JavaScript可让除数为零; var b = 26 / 0;//Infinity,表示无限大! console.log(typeof b); console.log(b); //string var c = '崔晓昭'; console.log(c); console.log(typeof c); //空字符串 var d = ""; console.log(d); console.log(typeof d); //字符串的拼接 //JavaScript中的+多是连字符也多是加法符号,表示运算; console.log('cui' + 'xiaozhao'); console.log(1 + 2 + 3); var e = 11 + ''; console.log(e); console.log("E的数据类型为:", typeof e); //boolean类型 // var isShow = false; // var isShow = true; var isShow = 1 == 1; console.log(typeof isShow);//boolean //null值 var f = null; console.log(typeof f); //undefined var g; console.log(g); console.log(typeof g); //复杂的(引用)数据类型: // Function def // Object dict // Array list // String string // Date time模块 </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <script type="text/javascript"> var x = 5; var y = '5'; console.log("2个等于号:", x == y);//比较的是值的相同; console.log("3个等于号:", x === y);//比较的是值和类型的相同,即内存地址; </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <script type="text/javascript"> //一、将number类型转换为string类型 var n1 = 123; var n2 = '123'; console.log(typeof n1); console.log(typeof n2); console.log(n1 + n2); console.log("n1+n2:", typeof (n1 + n2)); //二、强制转换String()或者toString() var str1 = String(n1); console.log(typeof str1); var num = 1234; console.log(num.toString()); //三、将string转换为number var strNum2 = '19939'; var num2 = Number(strNum2); console.log(typeof num2); console.log(num2); //四、一种特殊状况:NaN,Not a Number var strNum1 = '19930911.0911cxz'; var num1 = Number(strNum1); console.log(typeof num1); console.log(num1);//NaN:Not a number //parseInt(),parseFloat(),解析字符串,返回整数和小数; console.log(parseInt(strNum1));//19930911 console.log(parseFloat(strNum1));//19930911.0911 </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>JS中的流程控制</title> </head> <body> <script type="text/javascript"> //if; //if else if else; let age = 16; if (age == 18) { //{}做为当前的做用域; console.log('能够去会所了!'); } else if (age == 26) { console.log('该娶媳妇啦!') } else { console.log('随便你啦!'); } //js中的"逻辑与"与"逻辑或" let math = 91; let english = 85; if (math == 90 && english > 90) { console.log('小朋友,此次考试成绩还不错哦!') } else if (math < 90 || english > 90) { console.log('有一门课程考的还能够吧!') } else { console.log('好好加油!') } //做用域以外继续打印内容; console.log('做用域外的代码照样执行,和Python同样!'); alert('出现一个弹窗吧!') </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>07-js中的switch语句</title> </head> <body> <script type="text/javascript"> var gameScore = 'good911'; if (gameScore == 'good') { console.log('小朋友,你真好!') } else if (gameScore == 'better') { console.log('小朋友,你更好啦!') } else if (gameScore == 'best') { console.log('小朋友,你最好啦!') } else { console.log('小朋友,不知道如何夸赞你啦!') } //js中switch的用法学习; switch (gameScore) { case 'good': console.log('玩很很好呀!'); //swith语句,case是一个条件,只要遇到break跳出流程控制,若是break不写,程序会进入下一个break; //官方名称"case穿透"! break; case 'better': console.log('玩很geng好呀!'); break; case 'best': console.log('玩很最好啦!'); break; default: console.log('玩的不知所措了,下一次必定会吃鸡的...'); break; } </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>JS中的while循环</title> </head> <body> <script type="text/javascript"> /* 一、初始化循环变量; 二、判断循环条件; 三、更新循环变量; */ //举个例子; var i = 1; while (i <= 10) { if (i % 2 == 0) { console.log(i); } //i = i + 1; i += 1; } console.log('将0~100之间的偶数打印出来:'); var n = 0; while (n <= 100) { console.log(n); n += 2; } //do~while的用法; console.log('do~while的用法!'); var m = 1; do { console.log(m); m += 1; } while (m <= 11); </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>JS中的for循环</title> </head> <body> <script type="text/javascript"> //需求:打印1~100之间的数字; for (var i = 1; i <= 100; i++) { console.log(i) } //使用js输入1~100之间的整数之和; console.log('使用js输入1~100之间的整数之和;'); var sum = 0; for (var j = 1; j <= 100; j++) { sum += j; } console.log(sum); //新需求:使用js中的for循环,输入1~100之间2的倍数; console.log('新需求:使用js中的for循环,输入1~100之间2的倍数'); for (var m = 1; m <= 100; m++) { if (m % 2 == 0) { console.log(m); } } </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>JS中的双重for循环</title> </head> <body> <script type="text/javascript"> // 学习前的补充内容: document.write('cxz19930911'); document.write('<h1>崔晓昭</h1>'); document.write('<br/>'); //使用for循环进行循环写入; for (var i = 1; i <= 10; i++) { console.log(i); document.write('我爱你,中国!') } //需求01:使用js代码打印"直角三角形"; console.log('需求01:使用js代码打印"直角三角形";'); for (i = 1; i <= 6; i++) { for (var j = 1; j <= i; j++) { document.write('*'); } document.write('<br>'); } </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>11-JS中的数组Arra</title> </head> <body> <script type="text/javascript"> //JS中的数组Array,也能够叫作数组; //一、字面量方式建立数组; var colors = ['red', 'blue', 'green']; console.log(colors); console.log(window.colors);//其中,window能够省略不写; console.log(colors[0]); console.log(colors[1]); console.log(colors[2]); console.log(colors[-1]); console.log(colors[5]); //二、使用构造函数进行建立"数组" var types = new Array(); console.log(types); console.log(typeof types); types[0] = 'S'; types[1] = 'M'; types[2] = 'L'; types[3] = 'XL'; types[4] = 'XXL'; types[5] = 'XXXL'; console.log(types); for (var i = 0; i <= types.length; i++) { console.log(types[i-1]); } </script> </body> </html>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>12-JS中的数据的常见方法</title> </head> <body> <script type="text/javascript"> //一、数组的合并方法-concat; var south = ['上海', '杭州', '深圳', '成都']; var north = ['北京', '石家庄', '济南', '张家口']; var china = south.concat(north); console.log("中国南方的城市以下:", south); console.log("中国北方的城市以下:", north); console.log("南北方的城市群:", china); //二、将数组中的元素以指定的'字符串'链接起来,它会返回一个新的字符串; var birthday = [1993, 9, 11]; var birthdate = birthday.join('-'); console.log(birthdate); //三、切片;slice(start,end),返回数组中的一段记录,即切片,但顾头不顾尾; var arr = ['崔晓昭', '崔晓珊', '崔晓丝', '崔晓磊']; var newArr = arr.slice(1, 14); console.log(newArr); //四、push和pop方法; var nums = [12, 3, 4, 5, 6, 6, 9]; console.log(nums); nums.pop(); console.log(nums); nums.push(19930911); console.log(nums); //五、反转数组(reverse)和排序数组(sort); var names = ['cxz', 'cxs', 'cxl']; console.log(names); names.reverse(); console.log(names); names.sort(); console.log(names); //六、isArray判断是否是数组; var citys = 19930911; iscitys = Array.isArray(citys); if (iscitys) { console.log('他是一个数组'); } else { console.log('他不是一个数组'); } //七、遍历数组;forEach是一个回调函数,经过forEach来遍历数组中的每一项内容; //item为对象值,index为索引值; //注意Python中的列表方法和JavaScript中的不同,没有就是没有了; names2 = ['cxz', 'cxs', 'cxl']; names.forEach(function (item, index) { console.log(index + 1); console.log(item); }) </script> </body> </html>