【学习笔记】JavaScript：算数运算符和赋值运算符

1.  算术运算符

用于执行变量与/或值之间的算术运算。给定 y=5，下面的表格解释了这些算术运算符：

运算符                 描述                              例子                            结果

+                          加                                x=y+2                      x=7，y=5

-                           减                                x=y-2                       x=3，y=5

*                           乘                                x=y*2                       x=10，y=5

/                           除                                x=y/2                       x=2.5，y=5

%                         求余数 (保留整数)        x=y%2                     x=1，y=5

++                       累加                             x=++y                     x=6 ，y=6

--                         递减                             x=--y                       x=4 ，y=4

2.  赋值运算符

用于给 JavaScript 变量赋值。给定 x=10和 y=5，下面的表格解释了赋值运算符：

运算符                 例子                              等价于                            结果

=                          x=y                                                                     x=5，y=5

+=                       x+=y                              x=x+y                           x=15，y=5

-=                        x-=y                               x=x-y                            x=5，y=5

*=                        x*=y                               x=x*y                            x=50，y=5

/=                        x/=y                               x=x/y                            x=2，y=5

%=                      x%=y                              x=x%y                          x=0 ，y=5

3. 用于字符串的“+”运算符

    txt1="What a very";txt2="nice day";text3=text1+text2;text4=text1+""+text2;则，text3的值是"What a verynice day"，text4值是"What a very nice day"。

4. 如果把数字与字符串相加，结果将成为字符串。