/**
 * ScrollField.js
 * 2009-12-21 ver.0.0 Yuka.Irie
 *
 */
x = 0;
y = 0;
nx = 0;
ny = 0;
speed = 100;
move  = 5;
elementId = 'div01';
stop_flag = 0;

function _scrollUp(one){
    
    var obj = document.getElementById(elementId);
    var rep = setTimeout('_scrollUp()' , speed);

    if (stop_flag) clearTimeout(rep);
    
    obj.scrollTop += move;
    if(nx == obj.scrollTop || one){
        clearTimeout(rep);
    }else{
        nx = obj.scrollTop;
    }
}

function _scrollDown(one){
    
    var obj = document.getElementById(elementId);
    var rep = setTimeout('_scrollDown()' , speed);

    if (stop_flag) clearTimeout(rep);
    
    obj.scrollTop -= move;
    if(nx <= 0 || one){
        clearTimeout(rep);
    }else{
        nx = obj.scrollTop;
    }
}


function ScrollField(_elementId, _speed, _move)
{
    if ( _speed ) speed = _speed;
    if ( _move  ) move  = _move;
    if ( _elementId) elementId = _elementId;
    
    this.scrollUp = function(one){ stop_flag=0;_scrollUp(one) };
    
    this.scrollDown = function(one){ stop_flag=0;_scrollDown(one) };
    
    this.scrollStop = function(){
        stop_flag = 1;
    }
}