function pager() {
    this.selected = 0;
    this.lastpage = 0;    
}

pager.prototype = {
    setPager: function( num, show, active, prefixes ) {
        if ( prefixes == null ) {
            prefixes = new Array( 'top_', 'bottom_' );
        }
        for ( s in prefixes ) {
            var pager = prefixes[s] + 'pager_' + ( active ? 'active_' : ''  ) + num;
            document.getElementById( pager ).style.display = show ? 'block' :  'none';            
        }
    },

    setNextPager: function( show ) {
    },

    setPrevPager: function( show ) {
    },

    setPage: function( page, show ) {
        document.getElementById( 'page_' + page ).style.display = show ? 'block' :  'none';
    },

    setup: function( pages ) {
        this.lastpage = pages-1;
        this.setPage( 0, true );
        if ( this.lastpage > 0 ) {
            this.setGooglePager();
        }
    },


    
    setGooglePager: function() {
        var page_start = this.selected-2 > 0 ? (this.selected+2 < this.lastpage ? this.selected-2 : this.lastpage-4 ) : 0;
        var page_end = page_start + 4 < this.lastpage ? page_start + 4 : this.lastpage ;

        for (i = 0; i <= this.lastpage; i++) {
            this.setPager( i, false, true);
            this.setPager( i, false, false);
        }

        for (i = page_start; i <= page_end; i++) {
            if ( i == this.selected ) {
                this.setPager( i, true, true );
            } else {
                this.setPager( i, true, false );
            }
        }

    },

    next: function() {
        if ( this.selected !== this.lastpage ) {
            this.jumpToPage( this.selected+1 );
        }
    },

    prev: function() {
        if ( this.selected !== 0 ) {
            this.jumpToPage( this.selected-1 );
        }
    },

    jumpToPage: function( page ) {
        this.setPage( this.selected, false );
        this.setPage( page, true );

        this.selected = page;

        this.setGooglePager();

        this.setPager( page, true, true );

        if ( this.selected == 0 ) {
            this.setPrevPager( false );
        } else {
            this.setPrevPager( true );            
        }

        if ( this.selected == this.lastpage ) {
            this.setNextPager( false );
        } else {
            this.setNextPager( true );            
        }

    }
}