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 = 10
	let j = 1.1
	let x = 'etoak'
	let y = true
	let z = null
	
	
	//直接从页面输出
	document.write(`${i}+${j}=${i+j}
`
) document.write(`${i}+${x}=${i+x}
`
) document.write(`${i}+${y}=${i+y}
`
) document.write(`${i}+${z}=${i+z}
`
) document.write(`${j}+${x}=${j+x}
`
) document.write(`${j}+${y}=${j+y}
`
) document.write(`${j}+${z}=${j+z}
`
) document.write(`${y}+${x}=${y+x}
`
) document.write(`${z}+${x}=${z+x}
`
) } //运行结果 /** 10+1.1=11.1 10+etoak=10etoak 10+true=11 10+null=10 1.1+etoak=1.1etoak 1.1+true=2.1 1.1+null=1.1 true+etoak=trueetoak null+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 = 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')
				}

				let i = 10
				let j = 1.1
				let x = 'etoak'
				let y = true
				let z = null

				//直接从页面输出
				document.write(`${i}+${j}=${i+j}
`
) document.write(`${i}+${x}=${i+x}
`
) document.write(`${i}+${y}=${i+y}
`
) document.write(`${i}+${z}=${i+z}
`
) document.write(`${j}+${x}=${j+x}
`
) document.write(`${j}+${y}=${j+y}
`
) document.write(`${j}+${z}=${j+z}
`
) document.write(`${y}+${x}=${y+x}
`
) document.write(`${z}+${x}=${z+x}
`
) //在页面上使用document.write()来输出九九乘法表 let str = '' for(let a = 1;a<=9;a++){ for(let b = 1;b<=a;b++){ str += `${b}*${a}=${b*a}\t` } str += '
'
} document.write(str) }
script> body> html>

你可能感兴趣的:(#,JavaScript,javascript,开发语言,ecmascript)