valida cpf

cpf.js

function isCPF(value) {
    console.log(value);
    // value = jQuery.trim(value);
    cpf = value.toString(); //.replace(/.|-|/gi, ''); // elimina .(ponto), -(hifem) e /(barra)
    while (cpf.length < 11) cpf = "0" + cpf;
    var expReg = /^0+$|^1+$|^2+$|^3+$|^4+$|^5+$|^6+$|^7+$|^8+$|^9+$/;
    var a = [];
    var b = new Number;
    var c = 11;
    for (i = 0; i < 11; i++) {
        a[i] = cpf.charAt(i);
        if (i < 9) b += (a[i] * --c);
    }
    if ((x = b % 11) < 2) {
        a[9] = 0
    } else {
        a[9] = 11 - x
    }
    b = 0;
    c = 11;
    for (var y = 0; y < 10; y++) b += (a[y] * c--);
    if ((x = b % 11) < 2) {
        a[10] = 0;
    } else {
        a[10] = 11 - x;
    }
    if ((cpf.charAt(9) != a[9]) || (cpf.charAt(10) != a[10]) || cpf.match(expReg)) return false;
    return true;
}