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- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8">
- <meta name="viewport" content="width=device-width, initial-scale=1.0">
- <title>运算符</title>
- </head>
- <body>
- <script>
- var a = 1;
- var b = 2;
- var c = 10;
- var d = 5;
- console.log(a+b,'a+b')
- console.log(c-d,'c-d')
- console.log(a*b,'a*b')
- console.log(a/b,'a/b')
- // %取余
- console.log(b%c,'b%c')
- console.log(a + '23')//在加法运算中，number + string 这两种数据类型的时候 进行拼接
- console.log(b + '56')//256
- console.log('34'+'56')//在加法运算中，都是字符串时进行拼接
- console.log('ab'+b)//ab2
- console.log(true + c)//number时 true => 1(number) 11
- console.log(true + '34')//string时 true34
- console.log(true + false)//boolean时 true=>1 false=>0 1
- console.log(null + c)// 10
- console.log(undefined + c)//NaN 非法数字 无法运算
- console.log(c-d)//5 在减法运算中 number类型时 正常的减法运算
- console.log(c - '2')//8在减法运算中 number string(数字) 进行数据类型换算 可以进行减法运算
- console.log(c - '哈哈哈')//NaN
- console.log(c - 'hahaha')//NaN
- console.log(c - true)//9
- console.log(c - null)//10
- console.log(c - undefined)//NaN
- console.log(c * '2')// 20
- console.log(c * '哈哈哈')//NaN
- console.log(c * 'hahaha')//NaN
- console.log(c * d) // 50
- console.log(c * false)// 0
- console.log(c * null)// 0
- console.log(c * undefined)//NaN
- console.log(c / '2')//5
- console.log(c / 'hahah')//NaN
- console.log(c / false)//Infinity
- console.log(c / true)//10
- console.log(c / null)//Infinity
- console.log(c / undefined)//NaN
- </script>
- </body>
- </html>
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