JAVASCRIPT

card type through card number

function detectCardType(number) {
    var re = {
        electron: /^(4026|417500|4405|4508|4844|4913|4917)d+$/,
        maestro: /^(5018|5020|5038|5612|5893|6304|6759|6761|6762|6763|0604|6390)d+$/,
        dankort: /^(5019)d+$/,
        interpayment: /^(636)d+$/,
        unionpay: /^(62|88)d+$/,
        visa: /^4[0-9]{12}(?:[0-9]{3})?$/,
        mastercard: /^5[1-5][0-9]{14}$/,
        amex: /^3[47][0-9]{13}$/,
        diners: /^3(?:0[0-5]|[68][0-9])[0-9]{11}$/,
        discover: /^6(?:011|5[0-9]{2})[0-9]{12}$/,
        jcb: /^(?:2131|1800|35d{3})d{11}$/
    }

    for(var key in re) {
        if(re[key].test(number)) {
            return key
        }
    }
}