function addCommas( strValue ) {
	var objRegExp = new RegExp('(-?[0-9]+)([0-9]{3})'); 

	while(objRegExp.test(strValue)) {
		strValue = strValue.replace(objRegExp, '$1 $2');
	}
	return strValue;
}

var birthday =new Date(1987, 1, 5) ;
today = new Date();
var one_day=1000*60*60*24;
var days_since=Math.ceil((today.getTime()-birthday.getTime())/(one_day));

document.write(addCommas(days_since.toString()));