Question

Problem is: context variable _curIndex is set when there is first call of switchTo (at point a):

function ShowSwitcherObject( id, switchIds )
{

    this._id = id;

    this._isInited = false;

    this.isInited = function()
    {
        return this._isInited;
    };

    this._visible = false;

    this.show = function()
    {
        if( this._visible == false )
        {
            $( '#' + this._id ).show();
            this._visible = true;
            this._isInited = true;
        }
    };

    this._showSwitch = function()
    {
        $( '#' + this._switchIds[ this._curIndex ] ).show();
    };

    this._hideSwitch = function()
    {
        $( '#' + this._switchIds[ this._curIndex ] ).hide();
    };

    this.switchTo = function( index )
    {       
        if( index != this._curIndex ) // point a
        {
            if( this._curIndex != null )
            {
                this._hideSwitch();
            }

            this._curIndex = index; // point b
            this._showSwitch();
        }
    };
    this._switchIds = switchIds;
    return this;
}

It’s interesting that if we comment point b the variable is null at point a.
There are no external sets of _curIndex. It could be only set by switchTo. Is it firefox bug or something else?

Answer 1

From your code it seems this._curIndex would be undefined at point a.

If you need this._curIndex to be null, you must set it to null yourself, since the Javascript interpreter doesn’t resolve uninitialized variables to null, but rather undefined.

Try this instead:

this.switchTo = function( index )
{       
    if( index != this._curIndex ) // point a
    {
        if( typeof(this._curIndex) != 'undefined' )
        {
            this._hideSwitch();
        }

        this._curIndex = index; // point b
        this._showSwitch();
    }
};