The console.assert() method in HTML is used to write a message for the user on the console only if the expression evaluates to false. The expression and the message are sent as parameters to the console.assert() method.Â
Syntax
console.assert( expression, message )Parameters
This method accepts two parameters as mentioned above and described below:
- expression: A Boolean expression denotes the message or object to write to the console. It is a required parameter.
- message: A string or object denotes the message or object to write to the console. It is a required parameter.
Example 1: Below program illustrates the console.assert() method in HTML
<!--Driver Code Starts-->
<!DOCTYPE html>
<html>
<head>
<title>
DOM console.assert() Method
</title>
<style>
h1 {
color: green;
}
</style>
</head>
<body>
<h1>GeeksforGeeks</h1>
<h2>DOM console.assert() Method</h2>
<p>
To view the message in the console press the F12
key on your keyboard.
</p>
<!--Driver Code Ends-->
<script>
console.assert(document.getElementById("MyElement"),
"There is no element with the ID 'MyElement'");
</script>
<!--Driver Code Starts-->
</body>
</html>
<!--Driver Code Ends-->
Output:
Example 2: Displaying an object while using the console.assert() methodÂ
<!--Driver Code Starts-->
<!DOCTYPE html>
<html>
<head>
<title>DOM console.assert() Method</title>
<style>
h1 {
color: green;
}
</style>
</head>
<body>
<h1>GeeksforGeeks</h1>
<h2>DOM console.assert( ) Method</h2>
<p>
To view the message in the console press the
F12 key on your keyboard.
</p>
<!--Driver Code Ends-->
<script>
let MyElement = { Product: "Coca Cola", Type: "Beverage" };
console.assert(document.getElementById("MyDemo"), MyElement);
</script>
<!--Driver Code Starts-->
</body>
</html>
<!--Driver Code Ends-->
Output:
