Javascript Event Object

In traditional event registration model: function foo(e){console.log(e.type)} document.getElementById('#id').onclick=foo;//registered event handler But in inline event registratio

Solution 1:

Since event object being used within the click function is not passed by the browser we are manually passing it.

That's not correct. The browser (at least W3C compatible browser) pass the event object to the event handler.

The equivalent to

onclick="foo()"

is

elem.onclick = function(event) {
    foo();
};

The browser creates a function with event as first parameter and uses the value of the attribute as body of the function.

You have to pass the event object explicitly to foo because that's how JavaScript functions work. If you call a function inside another function, the outer function's parameters are not automatically passed to the inner function (that would be really confusing IMO).
Simpler example:

function foo(a) {
    bar();
}

function bar(a) {
    alert(a); // will show `undefined`
}

foo(42);