关于JS，+=连接字符串,为什么一定要前面加str +=才能连接啊？

Question

 var str = "窗口左边距离："+e.clientX+"，窗口顶边距离："+e.clientY;

                str += "\n网页左边距离："+e.pageX+"，网页顶边距离："+e.pageY;

                str += "\n屏幕左边距离："+e.screenX+"，屏幕顶边距离："+e.screenY;

                str += "\n事件类型："+e.type;

谢谢！

Answer 1

Regarding JS, += connection string, why must we add str += in front to connect? -PHP Chinese website Q&A-About JS, += connection string, why must we add str += in front to connect? -PHP Chinese website Q&A

Let’s take a look and learn.

Answer 2

str +=字符串  等于  str =str+字符串  这两个语句是相等的

上面的意思是把字符串加在str后面，组成一个整体的字符串