Array push action, can i improve the code

Question

I am using an Array push function to add elements to an array

var Oben = document.getElementById("Oben")
var Unten = document.getElementById("Unten")
if( Oben ) {
    objekte.push( Oben );
}
if( Unten ) {
    objekte.push( Unten );
}

Can i improve this coding style some how?

Answer 1

var Oben = document.getElementById("Oben");
var Unten = document.getElementById("Unten");

!Oben ||  objekte.push( Oben );
!Unten ||  objekte.push( Unten );

or

var Oben = document.getElementById("Oben");
var Unten = document.getElementById("Unten");

Oben &&  objekte.push( Oben );
Unten &&  objekte.push( Unten );

Answer 2

It's fine. But if you must:

function pushIfFound(list, id){
    var node = document.getElementById(id);
    if (node){
       list.push(node);
    }
}

pushIfFound(objekte, 'Oben');
pushIfFound(objekte, 'Unten');

Answer 3

To example, so:

var Oben = document.getElementById("Oben"),
    Unten = document.getElementById("Unten");

Answer 4

I probably wouldn't do this in real life as it's not the most intuitive for others to maintain but to do the comparison in one line:

var Oben = document.getElementById("Oben");
var Unten = document.getElementById("Unten");
objekte.push(Oben?Oben:Unten?Unten);