Question: I need your help.

I'd like to create a function that would add some zeros in front of a number. The maximum numbers of digits that the total string should have is 6. Here are examples:

```
     9 -> 000009
    14 -> 000014
   230 -> 000230
  1459 -> 001459
 21055 -> 021055
987632 -> 987632 (Do nothing, there's already 6 digits)

```

Answer: 
A simple one line solution without any loops
--------------------------------------------

Works with IE5-11, Firefox, Chrome, etc. Assumes integer input.

```
 function pad(n) { return ("000000" + n).slice(-6); }

```

**Run snippet to test:**

```html
<html>
<body>
<input id="stdin" placeholder="enter a number" maxlength="6"><button onclick="test()">Test</button>
<textarea id="stdout" style="width:100%;height:20em;padding:1em;"></textarea>
<script type="text/javascript">

   function pad(n) { return ("000000" + n).slice(-6); }

   function test() {
       var n = parseInt( document.getElementById('stdin').value);
       var e = document.getElementById('stdout').innerHTML += n + ' = ' + pad(n) + '\n';
   }

</script>
</body>
</html>
```
Recursive solution just for the heck of it:

```
function padNumberString(numberString) {
    if (numberString.length >= 6) {
        return numberString;
    }
    return padNumberString('0' + numberString);
}

```