Ever clicked a link only to find out that the image/download was massive and you wished you hadn’t? Wouldn’t it have been nice to have an idea of the file-size when hovering over the link?

function byteConvert(num) {
	var result = 0;
	var unit = "";
	
	// Set unit variables for convenience
	var bytes = 1;
	var kb = 1024;
	var mb = 1048576;
	var gb = 1073741824;

	// Check for non-numeric or negative num argument
	if (not isNumeric(num) OR num LT 0)
		return "Invalid size argument";
	
	// Check to see if unit was passed in, and if it is valid
	if ((ArrayLen(Arguments) GT 1)
		AND ("bytes,KB,MB,GB" contains Arguments[2]))
	{
		unit = Arguments[2];
	// If not, set unit depending on the size of num
	} else {
		  if      (num lt kb) {	unit ="bytes";
		} else if (num lt mb) {	unit ="KB";
		} else if (num lt gb) {	unit ="MB";
		} else                {	unit ="GB";
		}		
	}
	
	// Find the result by dividing num by the number represented by the unit
	result = num / Evaluate(unit);
	
	// Format the result
	if (result lt 10)
	{
		result = NumberFormat(Round(result * 100) / 100,"0.00");
	} else if (result lt 100) {
		result = NumberFormat(Round(result * 10) / 10,"90.0");
	} else {
		result = Round(result);
	}
	// Concatenate result and unit together for the return value
	return (result & " " & unit);
}