freeCodeCamp/guide/english/javascript/html-dom-queryselector/index.md

title
HTML DOM querySelector()

The Document method querySelector() returns the first Element within the document that matches the specified selector, or group of selectors. If no matches are found,null is returned.

HTML content:

<div id="id-example"></div>
<div class="class-example"></div>
<a>element-example</a> 

JavaScript content:

document.querySelector("#id-example"); // Returns the element with id "id-example"
document.querySelector(".class-example"); // Returns the element with class "class-example"
document.querySelector("a"); // Returns the "a" element 

Note querySelector() returns the first matching element, to return all the matches, use the querySelectorAll() method instead.

<div id="example">First</div>
<div id="example">Second</div>

document.querySelector("#example"); // Returns only the element containing 'First'

More Information:

MDN - document.querySelector()