posn=0; // Initialise variable

function cancelClick(){
    return false;
}

function greenArrow(mode, element){
    if(mode=="on"){
        newImg="/images/navSubBulletOver.gif";
    } else {
        newImg="/images/navSubBullet.gif";
    }

    document.getElementById(element).src=newImg;
}


function light(mode, element){
    if(mode=="on"){
        switch(element){
        case 'tla':
          newImg="/images/arrowTopLeftOver.gif";
          break;    
        case 'tra':
          newImg="/images/arrowTopRightOver.gif";
          break;
        case 'bla':
          newImg="/images/arrowBotLeftOver.gif";
          break;
        case 'bra':
          newImg="/images/arrowBotRightOver.gif";
          break;
        }

    } else {
        switch(element){
        case 'tla':
          newImg="/images/arrowTopLeft.gif";
          break;    
        case 'tra':
          newImg="/images/arrowTopRight.gif";
          break;
        case 'bla':
          newImg="/images/arrowBotLeft.gif";
          break;
        case 'bra':
          newImg="/images/arrowBotRight.gif";
          break;
        }
    }

    document.getElementById(element).src=newImg;
}

function getDivHeight(){
    return document.getElementById("scrollLeftCol").scrollHeight;
}

function scrollDiv(direc){
    maxDivHeight=getDivHeight()-document.getElementById("scrollLeftCol").clientHeight;
    // alert(getDivHeight() + ', ' + document.getElementById("scrollLeftCol").clientHeight + ', ' + maxDivHeight); // DEBUG

    if(direc=="top"){
         posn=0;
    }
    if(direc=="up" && posn > 0){
         posn=posn-containerHeight;
         if(posn < 0){ posn=0; }
    }
    if(direc=="down" && posn < maxDivHeight){
        posn=posn+containerHeight;
        if(posn > maxDivHeight){ posn=maxDivHeight; }
    }
    e=document.getElementById("scrollLeftCol");
    e.scrollTop=posn;

    return false;
}

function scrollDivTo(numTo){
    posn=0; // Goes nowhere if incorrect parameter is passed
    jump=containerHeight; // Amount to scroll by (in pixels)
    switch(numTo){
    case 1:
         posn=jump;
      break;    
    case 2:
         posn=jump * numTo;
      break;
    case 3:
         posn=jump * numTo;
      break;
    case 4:
         posn=jump * numTo;
      break;
    case 5:
         posn=jump * numTo;
      break;
    case 6:
         posn=jump * numTo;
      break;
    }

    e=document.getElementById("scrollLeftCol");
    e.scrollTop=posn;

    return false;
}