JavaScript console.assert() Method
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JavaScript console.assert() Method
The console.assert() method writes an error message to the console if the assertion is false. If the assertion is true, nothing happens.
Note: This feature is available in Web Workers.
Example
HTML Online Editor
<!DOCTYPE html>
<html>
<body>
<script>
console.assert(true, "I will not display");
console.assert(false, "I will display");
</script>
</body>
</html>
Syntax
console.assert(expression, msg)
Parameter Values
| Value | Type | Explanation |
|---|---|---|
| expression | Required | Any boolean expression. If the assertion is false, the message is written to the console. |
| msg | Required | A JavaScript string containing zero or more substitution strings. |
Real Time Example
In the following example, we will try to get an id of an element which is not available.
Example
HTML Online Editor
<!DOCTYPE html>
<html>
<body>
<script>
var x = document.getElementById("point");
console.assert(x, "id = 'point' not found");
</script>
</body>
</html>
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