Add Check Classes On A DOM Element as a javascript til

javascript/check-classes-on-a-dom-element.md

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+# Check Classes On A DOM Element
+
+You can use the [`classList`
+property](https://developer.mozilla.org/en-US/docs/Web/API/Element/classList)
+to check what classes have been assigned to a DOM element.
+
+Assuming the following DOM element:
+
+```html
+<div id="auth-modal" class="modal hidden">...</div>
+```
+
+Once you get a handle on that element, using your preferred method (e.g.
+[`Document.getElementById`](https://developer.mozilla.org/en-US/docs/Web/API/Document/getElementById)),
+you can start inspecting the class list:
+
+```javascript
+> element.classList.contains("modal")
+true
+
+> element.classList.contains("hidden")
+true
+
+> element.classList.contains("taco")
+false
+
+> element.classList.toString()
+"modal hidden"
+```