Question

I followed a little tutorial on Drag & Drop in HTML with Javascript, found here:

http://www.html5rocks.com/tutorials/dnd/basics/

The problem is, I’m working with an in-house style restriction. Meaning all documents have to be written to standards that everyone here uses.

For Javascript, one of them is to always write functions in the object-notation.

I.e.

var myFunction = function() {}

instead of

function myFunction() {}

In this tutorial, the events for the HTML5 drag & drop are added via the addEventHandler() function. This requires you use the normal notation, because if you use the object-notation, the addEventHandler() function trips over it for some reason.

I tried re-writing everything to be like this, without addEventHandler:

myElement.dragstart = function(e) {}

But non of it worked. Using the normal notation with addEventHandler however, everything works like a charm.
I just wanna make sure: am I overlooking something or should this work? Part of me suspects this is just not supported properly yet and you need to use addEventHandler. Is this the case?

Answer 1

Setting the dragstart property vs using addEventHandler('dragstart', ...) is not just a matter of notation. You can and should stick with addEventHandler. There should be no problem, however, using this "style:"

var myFunction = function() {}

myElement.addEventListener('dragstart', myFunction, ...);

---

Edit

Okay, so this doesn’t directly answer the question, but I feel it does need to be addressed in this context.

Writing

var myFunction = function() {}

instead of

function myFunction() {}

is not any sort of "object notation." The first is a function expression, since it’s part of an AssignmentExpression. The second is a function declaration. What’s the difference? kangax explains it really well:

First of all, function declarations are parsed and evaluated before any other expressions are. Even if declaration is positioned last in a source, it will be evaluated foremost any other expressions contained in a scope.
…
Another important trait of function declarations is that declaring them conditionally is non-standardized and varies across different environments. You should never rely on functions being declared conditionally and use function expressions instead.

Do the people who set the JavaScript code standards in-house really understand the subtle differences?