Example analysis of adding numbers and strings in javascript_javascript skills

复制代码 代码如下:

console.log('----1----')
console.log('12' '34')//'1234'
console.log('12' 34 )//'1234'
console.log(12 '34')//'1234'
console.log(12 34 )//46
console.log('----2----')
console.log( '12' '34')//'1234'
console.log( '12' 34 )//46
console.log( 12 '34')//'1234'
console.log( 12 34 )//46
console.log('----3----')
console.log(-'12' '34')//'-1234'
console.log(-'12' 34)//22
console.log(-12 '34')//'-1234'
console.log(-12 34)//22
console.log('----4----')
console.log('12' - '34')//-22
console.log('12' - 34)//-22
console.log(12 - '34')//-22
console.log(12 - 34)//-22
console.log('----5----')
console.log( '12' - '34')//-22
console.log( '12' - 34)//-22
console.log( 12 - '34')//-22
console.log( 12 - 34)//-22
console.log('----6----')
console.log(-'12' - '34')//-22
console.log(-'12' - 34)//-22
console.log(-12 - '34')//-22
console.log(-12 - 34)//-22

javascript中字符串连接的同时数字相加
document.write("")
假如i=1，以上代码输出为
如果想输出为2.jpg，应该这样写
document.write("")