Hexadecimal & Decimal Conversions

[Eric]

I know that you can use parseint to change them, but I wanted to do it all by hand. Tell me what you think, and feel free to use it.
var hex = '0123456789ABCDEF';
function d2h(num)
{
 if(num.toString().match(/\d/i))
 {
  var newHex = '';
  for(var getExp = 1; Math.pow(16,getExp)-1 < num; getExp++)
  {
  }
  getExp--;
  while(getExp >= 0)
  {
   for(var checkOk = 15; checkOk >= 0; checkOk--)
   {
    if(checkOk * Math.pow(16,getExp) <= num)
    {
     newHex += hex.charAt(checkOk);
     num -= (checkOk * Math.pow(16,getExp));
     getExp--;
     checkOk = -1;
    }
   }
  }
  if(newHex.length < 1)
   newHex = '0';
  return newHex;
 }else{
  alert("The number can only contain digits.");
  return 0;
 }
}
function h2d(hexnum)
{
 hexnum = hexnum.toString();
 if(hexnum.match(/[0-9A-Z]/i))
 {
  hexnum = hexnum.toUpperCase();
  var end = 0;
  for(var x = 0; x < hexnum.length; x++)
  {
   end += hex.indexOf(hexnum.charAt(x)) * Math.pow(16, hexnum.length - 1 - x);
  }
  return end;
 }else{
  alert("The hexadecimal number can only contain numbers 0 through 9 and letters A through F");
  return 0;
 }
}

[Peter]

Nice job Eric, works well.

Maybe take it a step further then parseInt(). With parseInt, you can only use 2 characters to get the decimal.

ie..

parseInt("FF", 16);

Take yours a step further so that if a user was to do...

h2d("FFFFFF");

...it would return 255255255, and maybe the other way as well.

Anyway, like I said, good job

[Eric]

Huh?

You got me confused there. I didn't use parseint if that's what you mean. I built it all from scratch.

It should be able to handle FFFFFF.

Edit:
Ah I see what you're saying. I'm doing this by true hex, I think what you are saying is the RGB hex, right?

[Peter]

Yeah, I think it would be more useful if it could allow for RBG hex, so FFFFFF could be inputted.