Lots of programming involves calculations with numbers. The problem comes when you want to display the result of your calculations and just printing the plain number isn't going to be good enough for what you want. You can of course format the number by adding commas and so forth but sometimes a number as a number isn't appropriate and you need the equivalent of the number in words. Converting a number into words isn't exactly the most straightforward of tasks but it can be done using javascript as the following number to word conversion form demonstrates.

// Convert numbers to words
// copyright 25th July 2006, by Stephen Chapman http://javascript.about.com
// permission to use this Javascript on your web page is granted
// provided that all of the code (including this copyright notice) is
// used exactly as shown (you can change the numbering system if you wish)

// American Numbering System
var th = ['','thousand','million', 'billion','trillion'];
// uncomment this line for English Number System
// var th = ['','thousand','million', 'milliard','billion'];

var dg = ['zero','one','two','three','four', 'five','six','seven','eight','nine']; var tn = ['ten','eleven','twelve','thirteen', 'fourteen','fifteen','sixteen', 'seventeen','eighteen','nineteen']; var tw = ['twenty','thirty','forty','fifty', 'sixty','seventy','eighty','ninety']; function toWords(s){s = s.toString(); s = s.replace(/[, ]/g,''); if (s != String(parseFloat(s))) return 'not a number'; var x = s.indexOf('.'); if (x == -1) x = s.length; if (x > 15) return 'too big'; var n = s.split(''); var str = ''; var sk = 0; for (var i=0; i < x; i++) {if ((x-i)%3==2) {if (n[i] == '1') {str += tn[Number(n[i+1])] + ' '; i++; sk=1;} else if (n[i]!=0) {str += tw[n[i]-2] + ' ';sk=1;}} else if (n[i]!=0) {str += dg[n[i]] +' '; if ((x-i)%3==0) str += 'hundred ';sk=1;} if ((x-i)%3==1) {if (sk) str += th[(x-i-1)/3] + ' ';sk=0;}} if (x != s.length) {var y = s.length; str += 'point '; for (var i=x+1; i<y; i++) str += dg[n[i]] +' ';} return str.replace(/s+/g,' ');}

<script type="text/javascript" src="toword.js">
</script>

var words = toWords(num);

http://javascript.about.com/library/bltoword.htm