/**** SmartScroll (C)2000-05 Stephen Chalmers ******************

 All donations to: http://www.hotspot.freeserve.co.uk/luv2payu/
 
 Provides CONTROLLABLE vertical auto scrolling of a document. 
 Best used to scroll frame windows containing long text passages.
 Retains functionality of the vertical scroll bar, which additionally 
 is used to change scroll direction. Any horizontal offset is preserved.

 Compatibility: NN4+ / Mozilla derivatives / IE4+ / Opera 5+

-- Installation --

 Assuming the script is saved as smartscroll.js
 
 <script type='text/javascript' src='smartscroll.js'></script>
 
 In the BODY tag, include: onload='SCstartScroll()'
 
 Optionally, set one or more user parameters thus:
 
 <script type='text/javascript'>
  SCdelay=130;  
  SCwrap=true;
  SCmouseOver=false;
  supportNN=true;
 </script>
 
 Their purpose is described below.
 
 -- Setup --

 To set the scroll speed, alter the value of 'SCdelay'. The higher the
 value, the slower the scrolling. Default == 100.

 There are two scroll modes, selected by setting the true/false state of 'SCwrap':
 
     Alternating [false] - scroll direction changes at each end. (Default)

     Wrap [true] - content scrolls upwards only, at bottom jumps back to top.

 When using Wrap mode, to allow the text to disappear off the screen and re-appear
 cleanly at the bottom, the page content should be padded with sufficient blank space,
 top and bottom.

 NOTE: Under Netscape 4.xx, if the page displays both scrollbars, scrolling may be erratic.
 If this is still likely to occur, set 'supportNN' to false.
 
 -- Operation --
 
 There are two control modes, selected by the true/false state of 'SCmouseover': 
 
 Mouseover [true] - Scrolling stops when the mouse is over the document and resumes 
 when it leaves.
 
 Click [false] - Toggle scrolling ON/OFF by clicking anywhere on the page (or scrollbar 
 on Gecko browsers).
 Toggle scroll direction with paired clicks anywhere on the page.
  
 In both modes, change scroll direction by moving the scrollbar in the desired direction, 
 or with the up/down cursor keys (frame must have focus).
 
 
*** Do not edit below this line (unless you can't resist it) ***/

var SCpageY=0, SCxPoint=0, SCyPoint=0,  SCup=-1, SCdn=1, SCdir=SCdn,     SCmoved, 
    SCoffsetType=0,  SColdY=-1,  SCtravel=0, SCcount=-1, SCScrollEnable=true,
    SCwait=1, SCpausedAt=0, 

    SCmouseOver=true,//  - User variables -
    SCdelay=100,     //  Alter these from script tags
    SCwrap=false,    //  within the calling document.
    supportNN=true;  // 
   

function SCgetPageX( idx )
{
 var r=0;
 
 switch(idx)
  {
   case 1 : r=window.pageXOffset;break
   case 2 : r=document.documentElement.scrollLeft;break;  
   case 3 : r=document.body.scrollLeft; 
  }  
  
 return r; 
}

function SCgetPageY( idx )
{
 var r=0;
 
 switch(idx)
  {
   case 1 : r=window.pageYOffset;break
   case 2 : r=document.documentElement.scrollTop;break;  
   case 3 : r=document.body.scrollTop; 
  }  
  
 return r; 
}
    
function SCSmartScroll()
{
 SCnow=new Date();

 if(SCScrollEnable)
  {
   if(SCpausedAt)      // paired-click detector
   {
    if(SCpausedAt+500 > SCnow.getTime()) // compare current time with pause time
     SCdir=-SCdir;
    SCpausedAt=0;
   }

   SCxPoint=SCgetPageX(SCoffsetType);
                                         // Read reported page position
   SCyPoint=SCgetPageY(SCoffsetType);

   if( (SCmoved=Math.abs(SCtravel=(SCyPoint-SColdY))) >2 ) // Check for deviant movement 
    {                                                   // caused by scrollbar use. 
     SCcount=-1;   
  
     if( (SCtravel<0 && SCdir==SCdn) || (SCtravel>0 && SCdir==SCup) )
      SCdir=-SCdir;
  
   	 SCpageY=SCyPoint;  // Update stored page position 
  	}
   else
    if(SCmoved>0)        // Check for movement.. 
     SCcount=-1;    
    else
     if(SCcount==-1)      // on failure start counter
      SCcount=SCwait;

   if(SCcount==-1)        
    SColdY=SCyPoint;     
   else                  // Wait period necessitated by NN, which intermittently
     {                   // delays reporting of correct Y position.
                                 
      if(SCcount==0)     //  No movement after wait period,
       {                  
        if(SCwrap==true && SCdir>0) // wrap
         SCpageY=0;     
        else
         SCpageY=SColdY; //  assume end reached and change direction 

        SCdir=-SCdir;
       }
  
       SCcount--;           
     }
 
    window.scrollTo(SCxPoint, SCpageY+=SCdir); // move page
 }
 else
  if(SCpausedAt==0)            // record time at pause
    SCpausedAt=SCnow.getTime();

 setTimeout("SCSmartScroll()",SCdelay);
}

function SCstartScroll()
{
 SCoffsetType=(window.pageXOffset!=null) ? 1 
       : ( document.compatMode && document.compatMode != 'BackCompat' ) ? 2
       : ( document.body && typeof(document.body.scrollTop)!='undefined') ? 3 
       : 0;
                               
 if( document.layers )
  if( supportNN==false )// Inhibit NN4 where selected.
   SCoffsetType=0; 
  else
   SCmouseOver=false; 

 if( SCoffsetType!=0 && window.scrollTo )
  {
   if(SCmouseOver)
    {   
     if(window.Event && document.captureEvents)
     {
      document.captureEvents(Event.MOUSEOVER);
      document.captureEvents(Event.MOUSEOUT);
     }
     document.onmouseout=function(){SCScrollEnable=true;};
     document.onmouseover=function(){SCScrollEnable=false;};
    } 
   else
    {
     if(window.Event && document.captureEvents)
      document.captureEvents(Event.MOUSEUP);  
     document.onmouseup=function(){SCScrollEnable^=true;}
    } 
       
   SCSmartScroll();
  }
}

//  fin