prototype
Summary
Returns a reference to the prototype for an error.
Syntax
error.prototype
Examples
For example, to add a method to the Error object that returns the value of the largest element of the array, declare the function, add it to Error.prototype , and then use it.
function getSeverity(){
if (this.number > 1000)
return "high";
else
return "low";
}
Error.prototype.getSev = getSeverity;
var myError = new Error();
myError.number = 5000;
document.write(myError.getSev());
// Output: high
Remarks
The error argument is the name of an error.
Use the prototype property to provide a base set of functionality to an Error. New instances of an object “inherit” the behavior of the prototype assigned to that object.
All intrinsic JavaScript objects have a prototype property that is read-only. Properties and methods may be added to the prototype, but the object may not be assigned a different prototype. However, user-defined objects may be assigned a new prototype.
Attributions
Microsoft Developer Network: Article