Error.parameterCount Function

Creates an Error object that represents the Sys.ParameterCountException exception.

var err = Error.parameterCount(message);

message

(Optional) An error message string. The value can be null. If message is null, a default message is used.

An Error object.

The parameterCount function lets you communicate that an exception has occurred when an invalid number of arguments have been passed to a function. The message argument enables you to specify additional error information.

The following example shows how to create, throw, and catch a Sys.ParameterCountException error by using the parameterCount function.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Sample</title>
</head>
<body>
    <form id="form1" runat="server">
       <asp:ScriptManager runat="server" ID="ScriptManager1">
       </asp:ScriptManager>

       <script type="text/javascript">

            function throwAnError(a, b) 
            {
                    if (arguments.length !== arguments.callee.length)
                    {
                        // Throw a standard exception.
                        var err = Error.parameterCount("Invalid number of parameters attempted."); 
                        throw err;
                    }
                    alert("No error occured.");
            }

        // Result: A Thrown Sys.ParameterCountException with the following message:
        // Error: Sys.ParameterCountException: Invalid number of parameters attempted.
        throwAnError(1,2,3,4);

       </script>
    </form>
</body>
</html>
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