js格式化货币格式

String.prototype.asCurrency = function() {var f1 = this;var f2 = (Math.round((f1-0) * 100)) / 100;f2 = Math.floor(f2) == f2 ? f2 + ".00" : (Math.floor(f2 * 10) == f2 * 10) ? f2 + '0' : f2;f2 = String(f2);r = /(\d+)(\d{3})/;fs = String(f2);while (r.test(f2)) {      f2 = f2.replace(r, '$1' + ',' + '$2');}return ('￥' + f2); // TODO 没考虑金额为负的情况}var s = "3.1415926";alert(s.asCurrency());