ranged rand generator

<html>
<head>
<title>bB ranged random number code generator</title>

<script>
 var mv, rg, nm, kf = "!k", jf = "!j", st

 function rnmb(p){return p.replace("!m",mv).replace(/!n/g,nm).replace(/!b/g,"<br>");}
 function ro(p){return p.replace("!o",st);}

 document.write("<pre><div id=\"text\" style=\"height:120px;\"></div><br>");
 document.write("<div id=\"btns\"></div><br>");
 document.write("<div id=\"bB\" style=\"height:20px;\"></div><br><br>");
 document.write("<div id=\"asm\" style=\"height:400px;\"></div></pre>");

 btns.innerHTML = "<input type=\"number\" id=\"minv\" min=\"0\" max=\"254\" value=\"0\" onchange= \"rrf()\">  ";
 btns.innerHTML += "<input type=\"number\" id=\"range\" min=\"2\" max=\"254\" value=\"2\" onchange= \"rrf()\">  ";
 btns.innerHTML+="<input type=\"text\" id=\"vnm\" size=\"16\" value=\"temp1\" onchange= \"rrf()\">  ";

 function rrf(){
 mv = Number(minv.value); rg=Number(range.value); nm=vnm.value
 if (mv+rg>255){rg = 255-mv;range.value=rg;}
 if("!2!4!8!16!32!64!128!".indexOf("!"+rg+"!")==-1){bbf();asmf();}else{p2f();}
 }

 function p2f(){
 var p = rg - 1;
 st = "rand & " + p;
 if (mv){st = ro("(!o) + !m");}
 bB.innerHTML = rnmb("  !n = " + st);
 st = "  asm!b  jsr randomize!b  and #!p!b".replace("!p",p);
 if (mv){st += "  clc!b  adc #!m!b";}
 st += "  sta !n!bend!b";
 asm.innerHTML = rnmb(st).replace("!p",p);
 }


 function bbf(){
 var i=rg,k=256,j=0;
 st="!n/";
 if (i>128){i++}
 while(i>=1){

   if(i&1){
     if(j){
       st=ro("!o!j + !n").replace(jf,i?j:k);
       if(k>2){st=ro("(!o)/");}
     }
     j=1;
   }
   i=i/2&255; j*=2;k/=2;
 }
 bB.innerHTML = rnmb("  !n = rand/2 : !n = " + st + (k>1?k:"")) + (mv?" + "+mv:"");
 }
function asmf(p){
 var i=rg,k=8;
 var st ="  asm!b  jsr randomize!b  sta !n!b  lsr!b";

 while((i&1)==0){i/=2;k--;}
 i/=2;k--;
 while(i>1){
   if (i&1==1){st+="  adc !n!b  ror!b";}
   else{st+="  lsr!b";}
   k--;i/=2;
 }
 while(k>0){st+="  lsr!b";k--;}
 if(mv){st+="  clc!b  adc #!m!b"}
 asm.innerHTML=rnmb(st + "  sta !n!bend!b");
 }

 text.innerHTML += "This script produces bB and asm code to return a range of random numbers<br>"
 text.innerHTML += "The number on the left is the first number in the range<br>"
 text.innerHTML += "The number in the middle is the number of numbers in the range<br>"
 text.innerHTML += "The text on the right is the name of the variable to use<br>"
 text.innerHTML += "So if you specify 5 as the first number and 15 as the range using<br>"
 text.innerHTML += "temp1 as your variable, you'll get numbers 5..14 in temp1 from the code<br>"
 text.innerHTML += "The asm is a little more accurate and has a more even distribution<br>"

 rrf();

</script>
</head>
<body style="background-color:#CCCCC8;font-family:"Arial">
</body>
</html>