javascript中的数字与字符串相加实例分析_javascript技巧-js教程-、刘德华、刘亦菲、谌洪

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 