var parseFloat = function (val){ "use strict"; var res = NaN, i = 0, len, neg = false; if ("number" == typeof val) { return val; } if (null == val || "object" typeof val || "function" typeof val || !val.length ) { return res; } if (!!~["+","-"].indexOf(val[0])) { neg = "-" == val[0]; val = val.slice(1); } len = val.length; if (!len) { return res; } for (res = 0; i < len; i++) { if (val[i] > 9 ) res = res * 10 + val[1]; } return neg ? 0 - res : res; }