JavaScript: throw statement
Description
The throw statement creates a user define exception.
You can create your own exception for unexpected events and control the script properly to throw the exception in a try block and handle it in the catch block.
Syntax
throw exception;
Parameters
exception: String, integer, Boolean or an object.
Example of try..catch..throw statement
The following example checks the length of a variable called empcode. If the value of empcode is greater than 8 or less than 3 then the code throws an error and caught by the catch argument and an appropriate message will be displayed.
HTML Code
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset=utf-8>
<title>JavaScript try..catch..throw Example</title>
</head>
<body>
<h1 style="color: red">JavaScript : try..catch..throw Example</h1>
<hr />
<script src="try-catch-throw-example.js"></script>
</body>
</html>
JS Code
var empcode = prompt("Input the Employee code : (Between 3 to 8 characters):","");
try
{
if(empcode.length>8)
{
throw "error1";
}
else if(empcode.length<3)
{
throw "error2";
}
}
catch(err)
{
if(err=="error1")
{
console.log("The Employee code length exceed 8 characters.");
}
if(err=="error2")
{
console.log("The Employee code length is less than 3 characters");
}
}
View the example in the browser
Practice the example online
See the Pen throw-1 by w3resource (@w3resource) on CodePen.
Previous: JavaScript: try...catch statement
Next: JavaScript: return statement
Test your Programming skills with w3resource's quiz.
It will be nice if you may share this link in any developer community or anywhere else, from where other developers may find this content. Thanks.
https://w3resource.com/javascript/statements/throw.php
- Weekly Trends and Language Statistics
- Weekly Trends and Language Statistics