---
# System prepended metadata

title: 搜尋欄頁作：判斷空字串&比對字串&消除默認動作
tags: [ALPHACampWeek6_學期2-2]

---

###### tags:`ALPHACampWeek6_學期2-2`

搜尋欄頁作：判斷空字串&比對字串&消除默認動作
===
判斷input是否為空字串
---
```jsx=

const keyword = searchInput.ariaValueMax.trim().toLowerCase();
  if(!keyword.length){
    return alert('Please enter a valid string')
  }

```
比對字串
---
- includes 
```jsx=
const str = 'AC Genie is so cute'
console.log(str.includes('Genie'))   // true
console.log(str.includes('genie'))   // false
console.log(str.includes('e is'))    // true  
console.log(str.includes('ut'))      // true
```
- match
```jsx=
else if (event.target.match('.btn-add-favorite')) {
    addToFavorite(parseInt(event.target.dataset.id))
  }


```
- event.matches
```jsx=
if (event.target.matches('.btn-add-favorite')) {
    // console.log(event.target)
    // console.log(parseInt(event.target.dataset.id))
    addToFavorite(parseInt(event.target.dataset.id))
  }
```
消除默認動作
---
```jsx=
event.preventDefault();
```


