I want to toggle the width of a div using a button. I'm not sure how to properly use an if-else statement to check the CSS, and I'm also not clear on the syntax. 

Let's assume that I have the following:

**CSS**

```
.firstDiv {
    border:1px solid black;
    padding:10px;
    width: 80px;
    margin:5px;
    display:relative;
}

```

**HTML**

```
<button id="boxToggle">Change Width</button>
<div class="firstDiv">
    <p>This is a paragraph.</p>
</div>

```

**JavaScript**

```
$("#boxToggle").click(function () {
    $("#firstDiv").css("width", "120px");
});

```

Right now, the JavaScript would only change the width once and not go back, but this still isn't working and I'm assuming that my syntax is wrong. 

A JSFiddle of the above can be found at the link.

<https://jsfiddle.net/647ye1pk/>

Any help is appreciated.