下記のコードは、"マウスストーカー(デジタル)"に『背景色ボタン』と『トグルボタン』をリンクさせたものですが、トグルボタンの表示が"clock on"⇔"clock off"でははなくて、"0"⇔"1"と表示されるところまで詰まって、その先は進みません。
どこに問題があるのか、ご教示いただけませんでしょうか？

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=shift_jis"> 
<TITLE>デジタル時計 - JavaScript</TITLE>
<style type="text/css">
<!--
.css{
    font-size:16px; 
    font-weight:bold;       
}
//-->
</style>


<script type="text/javascript"> 
<!--
function setTimeColors(color){
  if(moji){
    for(var i=0;i<moji.length;i++){
      var elem=document.getElementById("Time"+i);
      if(elem)elem.style.color=color;
    }
  }
}
function color1(){
  document.bgColor = "black";  
  document.fgColor = "gold";
  setTimeColors("red");
}
function color2(){
  document.bgColor = "red";
  document.fgColor = "grey";
  setTimeColors("purple");
}
function color3(){
  document.bgColor = "white";
  document.fgColor = "blue";
  setTimeColors("maroon");
}
// -->
</script>

<script type="text/javascript"><!--
msec=100;               //追従速度
fx=20;                  //表示位置ｘ座標
fy=-10;                 //表示位置y座標
fs=6;                   //文字の大きさ
fc="blue";              //文字色
F_face="Times New Roman";//フォント
//--------------------------------------

now=new Date();
(now.getHours()<10)?H="0"+now.getHours():H=now.getHours();
(now.getMinutes()<10)?M="0"+now.getMinutes():M=now.getMinutes();
(now.getSeconds()<10)?S="0"+now.getSeconds():S=now.getSeconds();

moji=H+":"+M+":"+S;

x=new Array();y=new Array();cnt = 0;
for (i=0; i<=moji.length; i++) {x[i] = -10;y[i] = -10; }
for(i=0;i<moji.length;i++){
  document.write(
    "<DIV style='position:absolute;z_index:2;top:-10px;left:-10px;' ID='Fonts"+i+"'>"
    +"<font face='"+F_face+"' size="+fs+" color="+fc+" ID='Time"+i+"'>"
    +moji.charAt(i)+"</font></DIV>");
}
function F_move(NNevent){
  if(document.all){
    x[0]=event.x;y[0]=event.y;
  }else{
    x[0]= NNevent.pageX;y[0]= NNevent.pageY;
  }
}
function F_run(){
  for (i=moji.length-1; i>=0; i--){
    if(i){x[i] = x[i-1]+fs*3;y[i] = y[i-1];}
    if(document.all){
      document.all("Fonts"+i).style.pixelTop=y[i]+fy+document.body.scrollTop;
      document.all("Fonts"+i).style.pixelLeft=x[i]+fx+document.body.scrollLeft;
    }else{
      document.getElementById("Fonts"+i).style.top=y[i]+fy+"px";
      document.getElementById("Fonts"+i).style.left=x[i]+fx+"px";
    }
  }
}
setInterval('F_run()',msec);
document.onmousemove = F_move;

function nowtime(){
  now=new Date();
  (now.getHours()<10)?H="0"+now.getHours():H=now.getHours();
  (now.getMinutes()<10)?M="0"+now.getMinutes():M=now.getMinutes();
  (now.getSeconds()<10)?S="0"+now.getSeconds():S=now.getSeconds();
  moji=H+":"+M+":"+S;

  for(i=0;i<moji.length;i++){
    document.getElementById("Time"+i).innerHTML=moji.charAt(i);
  }
}
setInterval("nowtime()",1000);

num = 0;
function toggle(){
 num ^= 1; 
document.getElementById("tog").value = num;
 if(num == 1){ 
 for(var i=0;i<moji.length;i++)
document.getElementById("Fonts"+i).style.visibility="visible";} 
else { 
 for(var i=0;i<moji.length;i++)
document.getElementById("Fonts"+i).style.visibility="hidden"; }
}
// -->
</script>
</HEAD>
<BODY>

<Font size="5"><b>デジタル時計</b></font> 

<center><p>
<INPUT style="BORDER-RIGHT: grey 1px solid; BORDER-TOP:
grey 1px solid; FONT-SIZE: 8pt; BORDER-LEFT: grey 
1px solid; COLOR: black; BORDER-BOTTOM: grey 1px solid;
FONT-FAMILY: ms gothic; BACKGROUND-COLOR: black"
onclick="color1();document.getElementById('text').style.color='lightblue';document.getElementById('text1').style.color='lightblue'" 
type="button" value="
　">
<INPUT style="BORDER-RIGHT: grey 1px solid; BORDER-TOP:
grey 1px solid; FONT-SIZE: 8pt; BORDER-LEFT: grey
1px solid; COLOR: black; BORDER-BOTTOM: grey 1px solid;
FONT-FAMILY: ms gothic; BACKGROUND-COLOR: red"
onclick="color2();document.getElementById('text').style.color='gold';document.getElementById('text1').style.color='gold'" 
type="button" value="
 ">
<INPUT style="BORDER-RIGHT: black 1px solid; BORDER-TOP:
grey 1px solid; FONT-SIZE: 8pt; BORDER-LEFT: grey 
1px solid; COLOR: black; BORDER-BOTTOM: grey 1px solid;
FONT-FAMILY: ms gothic; BACKGROUND-COLOR: white"
onclick="color3();document.getElementById('text').style.color='purple';document.getElementById('text1').style.color='purple'" 
type="button" value="
　">
</p></center>
<br><br><br><br>
<marquee class="css"><span id="text" style="font-size:30; color:green">"0"⇔"1"</span>ではなくて、<span id="text1" style="font-size:30; color:green">"clock off"⇔"clock on"</span>と切り替えて表示ようにするには？
</marquee>
<br><br><br><br><br><br>
<center><p>
 <input type="button" id="tog" value="clock OFF" onclick="toggle()">
</p></center>
</BODY>
</HTML>