Question: what's wrong with my code? For some reason my function load() does not change .firstDiv background?

I can't find any mistakes.

```js
function load() {
document.getElementsByClassName("firstDiv").style.backgroundImage = "url('https://static.pexels.com/photos/140945/pexels-photo-140945.jpeg')";
}
```

```css
.firstDiv, .secondDiv {
  width: 50%;
  height:100vh;
  float: left;
}

.firstDiv {
  background-image: url("https://static.pexels.com/photos/200303/pexels-photo-200303.jpeg");
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  box-shadow: inset 0 0 0 1000px rgba(0,0,0,.2);
  }
```

```html
<div class="firstDiv"></div>

<div class="secondDiv">
  <button onclick="load()">Change background</button>
</div>
```

Answer: 
Here's four ways to do it:

* > 
> git rebase <branch>
> 
> 
> 

Reset checked out branch to <branch>, apply differences (between
previous HEAD and the common ancestor) and commit.

```
git checkout my
git rebase beta

```
* > 
> git rebase <branch1> <branch2>
> 
> 
> 

Reset <branch2> to <branch1>, apply differences (between previous <branch2> and the common ancestor) and commit.

```
git rebase beta my

```
* > 
> git rebase --onto <branch1> <branch2>
> 
> 
> 

Reset checked out branch to <branch1>, apply differences (between previous HEAD and <branch2>) and commit.

```
git checkout my
git rebase --onto beta A2

```
* > 
> git rebase --onto <branch1> <branch2> <branch3>
> 
> 
> 

Reset <branch2> to <branch1>, apply differences (between previous HEAD and <branch2>) and commit.

```
git rebase --onto beta A2 my

```
If you are on top of your branch, just saying `git rebase beta` or `git rebase B2` will do. The difference is that by using --onto you can control more tricky situations..... like the opposite: want to move beta branch on top of my branch. If you are on top of beta and run `git rebase my-branch` you would end up with M1--M2--M3--A3'--A4'--A5'--B1'--B2' (because from the point where the branches diverged (A2) revisions A3 to A5 (both inclusive) would also have to be included in a simple rebase. In that case you would have to run: `git rebase --onto my-branch alpha-branch beta-branch`. Hope that clears it up