/* gives up and down scroll buttons to images, spans, ... named up_name, down_name, respectively.
// will keep the default scroll_box's style overflow if it encounters errors (so make overflow: auto;)                
// usage: put this after the scrollbox div:  var div_scroll1 = new TextScroll('div_scroll1', 'scroll_box'); */

                function TextScroll(scrollname, div_name, up_name, down_name)
                {
                    this.div_name = div_name;
                    this.name = scrollname;
                    this.scrollCursor = 0;
                    this.speed = 6;
                    this.timeoutID = 0;
                    this.div_obj = null;
                    this.up_name = up_name;
                    this.dn_name = down_name;
                
                {
                        if (document.getElementById) {
                            div_obj = document.getElementById(this.div_name);
                            if (div_obj) {
                                this.div_obj = div_obj;
                                this.div_obj.style.overflow = 'hidden';
                            }
                            div_up_obj = document.getElementById(this.up_name);
                            div_dn_obj = document.getElementById(this.dn_name);
                            if (div_up_obj && div_dn_obj) {
                                div_up_obj.onmouseover = function() { eval(scrollname + ".scrollUp();") };
                                div_up_obj.onmouseout = function() { eval(scrollname + ".stopScroll();") };
                                
                                div_dn_obj.onmouseover = function() { eval(scrollname + ".scrollDown();") };
                                div_dn_obj.onmouseout = function() { eval(scrollname + ".stopScroll();") };                            }
                        }
                    }
                
                this.stopScroll = function() {
                        clearTimeout(this.timeoutID);
                    }
                
                this.scrollUp = function() {
                        if (this.div_obj) {
                            this.scrollCursor = (this.scrollCursor - this.speed) < 0 ? 0 : this.scrollCursor - this.speed;
                            this.div_obj.scrollTop = this.scrollCursor;
                            this.timeoutID = setTimeout(this.name + ".scrollUp()", 60);
                        }
                    }
                
             this.scrollDown = function() {
                        if (this.div_obj) {
                            this.scrollCursor += this.speed;
                            this.div_obj.scrollTop = this.scrollCursor;
                            if (this.div_obj.scrollTop == this.scrollCursor) {
                                this.timeoutID = setTimeout(this.name + ".scrollDown()", 60);
                            } else {
                                this.scrollCursor = this.div_obj.scrollTop;
                            }
                        }
                    }


                            
                
                
                this.resetScroll = function() {
                        if (this.div_obj) {
                            this.div_obj.scrollTop = 0;
                            this.scrollCursor = 0;
                        }
                    }
                }