window.bg_slider = function( )
{
    this.bool_init                  = false;
    this.int_bg_position            = 0;
    this.bool_descending            = false;
    this.bool_title_highlighted     = false;
    this.int_ele_width              = 226;
}

window.bg_slider.prototype.constructie = function( string_targer_ele_id, string_title_ele_id, int_bg_height )
{
    this.dom_target_ele     = document.getElementById( string_targer_ele_id );
    this.dom_title_ele      = document.getElementById( string_title_ele_id );
    this.int_bg_height      = int_bg_height;
    
    if( !this.bool_init )
    {
        this.int_bg_position = this.int_ele_width - this.int_bg_height;
        this.bool_init       = true;
        var pointer          = this;
        
        setTimeout( function( ev ){ pointer.step( 50 ); pointer.step_title( 6000 ); }, 4000 );
    }
}

window.bg_slider.prototype.step = function( int_ms )
{
    var pointer = this;
    
    if( this.dom_target_ele )
    {        
        if( this.bool_descending )
        {
            this.int_bg_position--;
            
            if( this.int_bg_position + this.int_bg_height - this.int_ele_width <= 0 )
                this.bool_descending = false;
        }
        else
        {
            this.int_bg_position++;
            
            if( this.int_bg_position + this.int_bg_height >= this.int_bg_height )
                this.bool_descending = true;
        }
        
        this.dom_target_ele.style.backgroundPosition = "0 " + this.int_bg_position + "px";
    }
    
    setTimeout( function( ev ){ pointer.step( int_ms ); }, int_ms );
}

window.bg_slider.prototype.step_title = function( int_ms )
{
    var pointer = this;
        
    if( this.dom_title_ele )
    {
        if( !this.bool_title_highlighted )
            this.dom_title_ele.style.color = "#62B0FF";
            
        else
            this.dom_title_ele.style.color = "#00FF00";
            
            
        this.bool_title_highlighted = !this.bool_title_highlighted;
    }
    
    setTimeout( function( ev ){ pointer.step_title( int_ms ); }, int_ms );
}


if( !window.bg_slider_instance )
    window.bg_slider_instance = new window.bg_slider( );