# Number Base Converter in JavaScript : Number Base Converter « Security « JavaScript DHTML

Number Base Converter in JavaScript

```<html>
<head>
<!--
CryptoMX Tools
Copyright (C) 2004 - 2006 Derek Buitenhuis

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
-->
<title>Number Base Converter</title>
</head>
<body>
<script language=JavaScript>
<!--calc
function doBaseCon() {
form=document.forms[0];
from=form.from.value;to=form.to.value;val=""+form.val.value;

if(check(to,0)==1 || check(from,0)==1){form.res.value="Bases must be integer (excluding -1, 0, +1).";return;}
if(to==0 || from==0){form.res.value="That base is a mathematical impossibility.";return;}
if(to==-1 || to==1 || from==-1 || from==1){form.res.value="I don't think that base will work so well.";return;}

from=1*from;to=1*to;

txt=baseCon(from,to,val);

form.res.value=txt;

}
function check(n,dec) {
np=0;e=0;l=n.length;
for(r=0;r<l;r++) {
c=n.substring(r,r+1);
if(c<"0" || c>"9") {
e2=1;
if(c=="." && np==0 && dec==1){np++;e2=0;}
if((c=="+" || c=="-")&& r==0 && l>1){e2=0}
e=e | e2;
}
}if(n=="-." || n=="+.") return 1;
return e;
}

function clr() {
f=document.forms[0];
f.res.value="";
}

function format(num) {
if(""+num=="NaN"){return "Check that input."}

txt="";
if(num<0){txt+="-"; num*=-1}
for(n=0; n<11; n++) {
dig=Math.floor(num);
num=(num-dig)*10;
txt+=dig;
if(n==0)txt+=".";
}
return txt;
}

function baseCon(from,to,val) {
val2=baseXCon10(from,val);
if(""+val2=="nh")sum="No alpha-numerics in base "+from+" numbers."; else sum=base10ConX(to,val2);
return sum;

}
function baseXCon10(from,val){
val=""+val;sum=0;sgn=1;pl=0;div=1;
for(a=0;a<val.length;a++) {
ch=val.substring(a,a+1);
if(ch=="+" && a==0)sgn=1;
else {
if(ch=="-" && a==0)sgn=-1;
else {
if(ch==".")div=pl;
else {
if(ch>='0' && ch<='9')dg=1*ch;
ch=ch.toUpperCase();
if(ch=='A')dg=10;if(ch=='B')dg=11;if(ch=='C')dg=12;if(ch=='D')dg=13;if(ch=='E')dg=14;if(ch=='F')dg=15;
if(ch>='A' && ch<='Z' && from<=10 && from>0) {nh="nh"; return nh;}
sum+=Math.pow(from,pl)*dg;
pl--;
}
}
}

}
if(div==1)div=pl;
sum/=Math.pow(from,div+1);
if(sum>1000000 && sum-Math.floor(sum)<.000001) sum=Math.floor(sum);
if(sum>1000000 && Math.ceil(sum)-sum<.000001) sum=Math.ceil(sum);
sum*=sgn; round=1000000000000
sum=Math.floor(sum*round+.5)/round;
return sum;
}
function base10ConX(to,val) {
//to new
if(val<0){sgn="-";val=-val;}else{sgn="";}
sum="";

c=Math.floor(val);

start=0;rem=0;digits=0;
if(c==0)sum="0";
while(Math.abs(c)>=1) {
d=c-Math.floor(c/to)*to;
dfl=Math.floor(d);
if(dfl!=d){rem=d-dfl;d=dfl;}
if(Math.abs(d)>Math.abs(to)) d=0;
c=Math.floor(c/to);
if((start==0 && d!=0) || c<val*to)start=1;start=1;
sum=""+alp(d,to)+sum;
digits++;

}
c=val-Math.floor(val)+rem;
if(c!=0) {//decimals
sum+=".";
for(a=0;a<32/Math.log(to)-digits;a++) {
if(c==0)break;
d=Math.floor(c*to);
if(to<0 && d==to) break;
c=c*to-d;
sum+=alp(d,to);
}
}
sum=sgn+sum;

return sum;
}
function alp(d,to) {
if(d>=0 && d<=9)w=""+d;
if(to>=10 && to<=36) {
if(d==10)w="A";if(d==11)w="B";if(d==12)w="C";if(d==13)w="D";if(d==14)w="E";if(d==15)w="F";if(d==16)w="G";if(d==17)w="H";if(d==18)w="I";if(d==19)w="J";if(d==20)w="K";if(d==21)w="L";if(d==22)w="M";if(d==23)w="N";if(d==24)w="o";if(d==25)w="P";if(d==26)w="Q";if(d==27)w="R";if(d==28)w="S";if(d==29)w="T";if(d==20)w="U";if(d==31)w="V";if(d==32)w="W";if(d==33)w="X";if(d==34)w="Y";if(d==35)w="Z";
}
if(d<0 || d>35 || (d>9 && to>36))
w="["+d+"]";
return w;
}

//-->
</script>
<td>&nbsp;&nbsp;</td>
<td vAlign=top>
<p><font color=#000000 size=5><b>Number Base Converter</b></font></p>
<p><font color=#000000 size=3>Convert numbers from one base to another.</font></p>
<table cellSpacing=0 cellPadding=3 border=1>
<form name=inp>
<tbody>
<tr bgColor=#ffffff>
<td>from base</td>
<td>to base</td>
<td>value to convert</td></tr>
<tr bgColor=#ffffff>
<td><input onmousedown=clr() size=5 value=10 name=from> </td>
<td><input onmousedown=clr() size=5 value=16 name=to> </td>
<td><input onmousedown=clr() size=50 value=256 name=val> </td></tr>
<tr bgColor=#ffffff>
<td><input onclick=doBaseCon() type=button value=calculate name=button>
</td>
<td colSpan=2><input size=50 name=res> </td></tr></form></tbody></table>
</td>
</tr>
</body>
</html>

```