In this tutorial we will learn How To Check If id Exists with JavaScript. getElementById() method can be used along with if else statements to check if id exists on a page or not.
Table of Contents
getElementById() method
getElementById() method selects or targets the HTML element based on it's id.
In this example getElementById() method is used to select the paragraph tag with it's id.
HTML Code
HTML Code is given below, in this code we have a paragraph tag with id named 'red' and a button tag with onclick event.
<!DOCTYPE html>
<html>
<head>
<title>Check If id Exists JavaScript</title>
<style>
#red
{
background-color: red;
padding: 10px;
}
</style>
</head>
<body>
<p id="red">My id is "Red"!</p>
<button onclick="checkId()">Check</button>
<script src="script.js"></script>
</body>
</html>
JavaScript Code
Take a look at the JavaScript code, the code will be executed on a click of button with the help of onclick event.
In this code getElementById() method is used to get the element with defined id. Then if else statements are used to check if that element with defined id exists or not.
alert() method is used to output the result.
<script>
function checkId()
{
var id = document.getElementById('red');
if(id)
{
alert("id exists!");
}
else
{
alert("id doesn't exist");
}
}
</script>
Demo
Video Tutorial
Watch video tutorial on How To Check If id Exists in JavaScript.