Javascript DOM HTML Element querySelector() Method

Introduction

Change the text of the first child element with class="example" in a <div> element:

Click the button to change the text of the first element with class="example" in div.

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<!DOCTYPE html>
<html>
<head>
<style>
#myDIV {/*from   w w  w.  j  av  a 2  s  .  c  o m*/
  border: 1px solid black;
}
</style>
</head>
<body>

<div id="myDIV">
  <h2 class="example">A heading with class="example" in div</h2>
  <p class="example">A paragraph with class="example" in div.</p>
</div>

<button onclick="myFunction()">Test</button>

<script>
function myFunction() {
  var x = document.getElementById("myDIV");
  x.querySelector(".example").innerHTML = "Hello World!";
}
</script>

</body>
</html>

The querySelector() method returns the first child element that matches a CSS selector(s).

The querySelector() method only returns the first element that matches the specified selectors.

To return all the matches, use the querySelectorAll() method instead. 

element.querySelector(CSS-selectors);

Parameter Values

Parameter Type Description
CSS-selectors String Required. Specifies one or more CSS selectors to match the element.

For multiple selectors, separate each selector with a comma.

The returned element depends on which element that is first found in the document.

If no matches are found, null is returned.

The querySelector() throws a SYNTAX_ERR exception if the specified selector(s) is invalid.




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