JavaScript 基础语法

文章目录

- 逻辑控制语句
- 直接从页面输出
- 数据类型相加
- 循环语句
- 测试语法

逻辑控制语句

function print(){//注意常量尽量全部使用大写const SEASON = 3	if(SEASON>=1&&SEASON<=3){console.log('春天来了')}else if(SEASON>=4&&SEASON<=6){console.log('夏天来了')}else if(SEASON>=7&&SEASON<=9){console.log('秋天来了')}else if(SEASON>=10&&SEASON<=12){console.log('冬天来了')}
}

直接从页面输出

function writeHello(){document.write(`hello`)
}

数据类型相加

function test(){let i = 10let j = 1.1let x = 'etoak'let y = truelet z = null//直接从页面输出document.write(`${i}+${j}=${i+j}<br>`)document.write(`${i}+${x}=${i+x}<br>`)document.write(`${i}+${y}=${i+y}<br>`)document.write(`${i}+${z}=${i+z}<br>`)document.write(`${j}+${x}=${j+x}<br>`)document.write(`${j}+${y}=${j+y}<br>`)document.write(`${j}+${z}=${j+z}<br>`)document.write(`${y}+${x}=${y+x}<br>`)document.write(`${z}+${x}=${z+x}<br>`)
}
//运行结果
/**10+1.1=11.110+etoak=10etoak10+true=1110+null=101.1+etoak=1.1etoak1.1+true=2.11.1+null=1.1true+etoak=trueetoaknull+etoak=nulletoak
*/

循环语句

function test（）{for(let a = 1;a<=9;a++){console.log(a )}
}

测试语法

<!DOCTYPE html>
<html lang="zh-CN"><head><meta charset="UTF-8"><title>测试</title></head><body onload="etoak('hello','你好')"><script>//此处函数中传递的为形参，形参标识符可以随意书写，注意避免五种字符function etoak(arg1,arg2){alert(`${arg1}world,${arg2}世界~~`)//注意常量尽量全部使用大写const SEASON = 3if(SEASON>=1&&SEASON<=3){console.log('春天来了')}else if(SEASON>=4&&SEASON<=6){console.log('夏天来了')}else if(SEASON>=7&&SEASON<=9){console.log('秋天来了')}else if(SEASON>=10&&SEASON<=12){console.log('冬天来了')}let i = 10let j = 1.1let x = 'etoak'let y = truelet z = null//直接从页面输出document.write(`${i}+${j}=${i+j}<br>`)document.write(`${i}+${x}=${i+x}<br>`)document.write(`${i}+${y}=${i+y}<br>`)document.write(`${i}+${z}=${i+z}<br>`)document.write(`${j}+${x}=${j+x}<br>`)document.write(`${j}+${y}=${j+y}<br>`)document.write(`${j}+${z}=${j+z}<br>`)document.write(`${y}+${x}=${y+x}<br>`)document.write(`${z}+${x}=${z+x}<br>`)//在页面上使用document.write()来输出九九乘法表let str = ''for(let a = 1;a<=9;a++){for(let b = 1;b<=a;b++){str += `${b}*${a}=${b*a}\t`}str += '<br />'}document.write(str)}</script></body>
</html>