Just a basic "start" for those who are interested in OOP Javascript programming and string manipulation. Add commas to you whole number string. Some validation included... No rounding and no decimal places (other than those that are hard-coded).
Code
<!-Header Script-->
function recurseMe(xPrompt)
{
this.x = xPrompt;
this.y = 3;
this.z = ",";
if (isNaN(xPrompt) || (xPrompt.indexOf(".") > 0))
{
alert("This is not a numerical string or a whole number.n" +
"Please try again.");
return false;
}else{
recurseMe.prototype.rString(this.x,this.y,this.z);
}
delete this.x;
delete this.y;
delete this.z;
}
recurseMe.prototype.rString = function(x,y,z)
{
var b = "";
var gArray = new Array(x.length);
for (var i = x.length - 1; i >= 0; i--)
{
if (y == 0)
{
gArray[i] = x.charAt(i) + z;
y = 2;
}else{
gArray[i] = x.charAt(i);
y -= 1;
}
}
recurseMe.prototype.setRight(gArray,i,b);
}
recurseMe.prototype.setRight = function(gArray,i,b)
{
for (var i = 0; i < gArray.length; i++)
{b += gArray[i];}
init(b);
}
function init(jString)
{
if (jString == '')
{
var fPrompt = prompt("Enter a whole number","0");
var x = new recurseMe(fPrompt);
}else{
document.testNum.num.value = "$" + jString + ".00";
}
}
<!-Body-->
<form name = "testNum">
<input type = "text" name = "num" value = "">
<input type = "button" value = "Execute" onclick = "javascript:var jString = '';init(jString);">
</form>