:The const declaration creates a read-only reference to a value. It does not mean the value it holds is immutable, just that the variable identifier cannot be reassigned. For instance, in the case where the content is an object, this means the object's contents (e.g., its properties) can be altered.具体解释就是,变量在编译链接后会被分配到具体的某个内存地址,变量值是该地址存储的内容。用const初始化变量,就是将初始变量值分配到指定内存地址。此时内存地址已经确定不能变,再赋值会将这个变量分配到别的地址,报错;而地址中存储的变量值可以被修改。