addEventListener to non-HTML object?

[Greg A]

What I am unsuccessful at doing is adding the event listener to an object in memory which isn't referencing an HTML element:

// DATA OBJECT CONSTRUCTOR
function dataObject(id){ 
 
    //  EVENT
    this.addEventListener("error",function(event){this.err(event)},true);
 
    // METHOD
    this.err = function(e){
        // ERROR HANDLING HERE
    }
 
}
 

I get this error in my error console:

this.addEventListener is not a function

Perhaps I don't fully understand the exact behavior of events and which objects can raise them.

I am able, however, to use addEventListener to an HTML object. This works fine:

// DIV OBJECT CONSTRUCTOR
function divObject(id){ 
 
    // ELEMENT
    var div = document.getElementById(id);
 
    //  EVENT
    div.addEventListener("error",function(event){div.err(event)},true);
 
    // METHOD
    this.err = function(e){
        // ERROR HANDLING HERE
    }
 
}
 

My aim is to add an event to an object, and trap errors if they should occur in the code blocks inside. Is this possible?

[mrhoo]

In any language, this.someMethod() will only function if the object of this has a someMethod method defined for it. You need to define the method, or co-opt a method of an existing object, by reference.

[Greg A]

In any language, this.someMethod() will only function if the object of this has a someMethod method defined for it. You need to define the method, or co-opt a method of an existing object, by reference.

Thanks for the quick reply.

If I hear you correctly, I must first write a method using this.methodName before I can call it...hence the "this.addEventListener is not a function" error. It's treating "addEventListener" as a user-defined method in my object and assumes it's a reference error.

Ok, so moving on from here...is there a way to add an event listener to an object so I can raise events with the onerror event type?

The purpose would be for detecting errors inside of objects without enclosing the entire code block with a try/catch.

If this is possible, error reporting/suppression would be much easier - since I would be able to report the name of the object from which the onerror event was fired with arguments.callee.name. And, it would allow me to suppress any/all errors within the object, and it would simply die without kicking and screaming.

Maybe I'm dreaming too big here.

[dmjpro]

What I am unsuccessful at doing is adding the event listener to an object in memory which isn't referencing an HTML element:

// DATA OBJECT CONSTRUCTOR
function dataObject(id){ 
 
    //  EVENT
    this.addEventListener("error",function(event){this.err(event)},true);
 
    // METHOD
    this.err = function(e){
        // ERROR HANDLING HERE
    }
 
}
 

I get this error in my error console:

this.addEventListener is not a function

Perhaps I don't fully understand the exact behavior of events and which objects can raise them.

I am able, however, to use addEventListener to an HTML object. This works fine:

// DIV OBJECT CONSTRUCTOR
function divObject(id){ 
 
    // ELEMENT
    var div = document.getElementById(id);
 
    //  EVENT
    div.addEventListener("error",function(event){div.err(event)},true);
 
    // METHOD
    this.err = function(e){
        // ERROR HANDLING HERE
    }
 
}
 

My aim is to add an event to an object, and trap errors if they should occur in the code blocks inside. Is this possible?

Use try catch blocks.

try{
//some code
}catch(e){
//some code
}
 

Good Luck!

Kind regards,
Dmjpro.