> For the complete documentation index, see [llms.txt](https://jen-hsuan-hsieh.gitbook.io/javascript-node-js/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jen-hsuan-hsieh.gitbook.io/javascript-node-js/chapter1/12javascript-quan-gong-lve-ff1a-ke-fu-js-de-qi-guai-bu-fen/123wu-jian-yu-han-shu/12313wei-xian-xiao-ding-ning-ff1a-zi-dong-cha-ru-fen-hao.md).

# 1.2.3.13.危險小叮嚀：自動插入分號

* 當按下enter時就會出現一個carriage return, 是一個看不到的字元
  * 此時JavaScript engine會自動加入分號, 所以寫程式時才不需要加上分號
* 因此**在寫JavaScript時會將大括號放在跟函數, for迴圈, if陳述式同一行**

```
function getPerson(){
    return 
    {
        firstname: 'Tony'
    }
}


//印出undefined
console.log(getPerson());

//因為JavaScript engine會自動加入分號:
function getPerson(){
    return;
    {
        firstname: 'Tony'
    }
}

//必須預防自動加入分號: 將大括號放在跟函數, for迴圈, if陳述式同一行
function getPerson(){
    return {
        firstname: 'Tony'
    }
}
```