Not A Script

window.addEventListener("DOMContentLoaded", function() {

    var element = document.querySelector("#main > form");

    var a = document.querySelector("#cimg1 > img").src;
    var b = document.querySelector("#cimg2 > img").src;
    var c = document.querySelector("#cimg3 > img").src;

    var a1 = String(a).slice(36,37);
    var b1 = String(b).slice(36,37);
    var c1 = String(c).slice(36,37);

    var input = String(a1+b1+c1);
        document.querySelector("#main > form > div:nth-child(3) > input[type=text]").value = input;

    var but = document.querySelector("#main > form > div:nth-child(6) > input[type=button]");
        but.addEventListener ("click", function() {
           document.querySelector("#main > form > div:nth-child(3) > input[type=text]").value = input;
                window.location.reload();
    });

    but.click();
}, false);