a javascript exception demo

exception_demo.js

function defineException(name) {
	var Exception = function(message) {
		this.message = message;
	}
	Exception.prototype.name = name;
	return Exception; 
}

var ValueException = defineException("ValueException");
var AssertException = defineException("AssertException");

try {
	throw new ValueException("Demo");
} catch(e) {
	if (e instanceof ValueException) {
		console.log("ValueException" + e.message);
	}
	if (e instanceof AssertException) {
		console.log("ValueException" + e.message);
	}
}