I know that in JS, objects are passed by reference, for example:

function test(obj) {

    obj.name = 'new name';

}



var my_obj = { name: 'foo' };

test(my_obj);

alert(my_obj.name); // new name

But why doesn't the below work:

function test(obj) {

    obj = {};

}



var my_obj = { name: 'foo' };

test(my_obj);

alert(my_obj.name); // foo

I have set the object to {} (empty) but it still says foo.

Can any one explain the logic behind this?