国际通用命名规则<html lang="en">
<head>
<meta charset="UTF-8">
<title>命名规则</title>
</head>
<body>
<!--国际通用的命名规则：驼峰法则
<一：变量>
1：单个单词的全小写
var name = "lzw";
2：多个单词 第一个单词全小写，其余单词首字母大写
var myName = "lzw";
var showHelloWord = "HelloWord";
<二：类>
3：全部单词的首字母都要大写
PersonName
<三：常量>
4：所有单词的字母全大写
COUNTRYNAME
-->
<!--类和常量与Java相关-->
</body>
<script>
var name = "lzw";
var myName = "lzw";
</script>
</html>
Number函数<html lang="en">
<head>
<meta charset="UTF-8">
<title>Number函数</title>
</head>
<body>
<script>
var b = "1";
var i = 1;
alert(b === i);
/*alert(Number(true));*/
</script>
</body>
</html>
结果图：
Typeof类型<html lang="en">
<head>
<meta charset="UTF-8">
<title>Typeof</title>
</head>
<body>
<script>
/*undefined*/
var i;
// alert(typeof i);
/*boolean*/
var b = true;
// alert(typeof b);
/*string*/
var s = "lzw";
// alert(typeof s);
/*number*/
var i = 3;
// alert(typeof i);
var obj = {
name:"lzw",
age:"保密"
}
// alert(typeof obj);
function show() {
alert("hello");
}
alert(typeof show);
</script>
</body>
</html>
结果图：
Prompt<html lang="en">
<head>
<meta charset="UTF-8">
<title>Prompt</title>
</head>
<body>
<script>
var name = prompt("请输入用户姓名","张三");
alert(name);
</script>
</body>
</html>
结果图：
自增自减<html lang="en">
<head>
<meta charset="UTF-8">
<title>自增自减</title>
</head>
<body>
<!-- ++自增运算
1：++在运算数的前面：先+1 再运算
2：++在运算数的后面：先运算 再+1
-->
<script>
/* var i = 2;
j = i++;
alert(j);
alert(i);*/
var i = 2;
j = ++i;
alert(j);
alert(i);
</script>
</body>
</html>
结果图：
水仙花数<html lang="en">
<head>
<meta charset="UTF-8">
<title>水仙花数</title>
</head>
<body>
<script>
var num = 153;
var n1 = parseInt(num/100);
var n2 = parseInt(num/10%10);
var n3 = parseInt(num%10);
var result = n1*n1*n1+n2*n2*n2+n3*n3*n3;
Math.pow(n1,3)+Math.pow(n2,3)+Math.pow(n3,3);
if (num == result){
alert("是水仙花数！！")}
else{
alert("非水仙花数！！")
}
</script>
</body>
</html>
结果图：
赋值运算符<html lang="en">
<head>
<meta charset="UTF-8">
<title>赋值运算符</title>
</head>
<body>
<script>
var i = 5;
i += 5; // 等效 i +=5; 效率高
alert(i);
var i2 = 10;
i2 -= 7;// i2 = i2 - 7;
var i3 = 6;
i3 = i3 * 6; // i3 *= 6;
var i4 = 12;
i4 = i4 / 3; // i4 /= 3;
var i5 = 16;
i5 = i5 % 6;// i5 %= 6;
</script>
</body>
</html>
结果图：
if-else语句<html lang="en">
<head>
<meta charset="UTF-8">
<title>if-else</title>
</head>
<body>
<script>
var i = parseInt(prompt("输入分数"));
if (i >= 90) {
alert("优");
}
else if ( i >= 80) {
alert("良");
}
else if ( i >= 60) {
alert("中");
}
else {
alert("差");
}
</script>
</body>
</html>
结果图：
嵌套if结构
<html lang="en">
<head>
<meta charset="UTF-8">
<title>嵌套if结构</title>
</head>
<body>
<script>
var score = parseInt(prompt("考试成绩"));
var daily = parseInt(prompt("考勤成绩"));
if (score >= 60 && daily >= 75) {
alert("毕业");
}
else {
if (score < 60 && daily < 75) {
alert("都不合格");
}
else if (score < 60) {
alert("考试不合格");
}
else if (daily < 75) {
alert("考勤不合格");
}
}
</script>
</body>
</html>
结果图：
switch-case语句
<html lang="en">
<head>
<meta charset="UTF-8">
<title>switch-case</title>
</head>
<body>
<script>
var month = parseInt(prompt("请输入月份"));
switch (month){
case 1:
alert("第一季度");
break;
case 2:
alert("第一季度");
break;
case 3:
alert("第一季度");
break;
case 4:
alert("第二季度");
break;
case 5:
alert("第二季度");
break;
case 6:
alert("第二季度");
break;
case 7:
alert("第三季度");
break;
case 8:
alert("第三季度");
break;
case 9:
alert("第三季度");
break;
case 10:
alert("第四季度");
break;
case 11:
alert("第四季度");
break;
case 12:
alert("第四季度");
break;
default:
alert("输入的月份有误");
break;
}
</script>
</body>
</html>
结果图：
时间： 2024-10-26 00:29:34