function captcha_refresh(image) 
{
    var element = document.getElementById(image);
    var posistion = element.src.indexOf("?");
    if (posistion == -1) {
        posistion = element.src.length;   
    }
    element.src = element.src.substring(0, posistion) + "?" + Math.round((Math.random()*10000000));
}