function updateCaptcha(){
    var params = updateCaptcha.arguments;
    var paramsLength = updateCaptcha.arguments.length;
    var num = '';
    var extra = '';
    var width = '';
    var height = '';

    if(paramsLength >0){
        var num = (params[0] != '') ? params[0] : '';
        var extra = (params[1] != '') ? params[1] : '';
        var width = (params[2] != '') ? params[2] : '';
        var height = (params[4] != '') ? params[3] : '';
    }

    document.getElementById('captchaCode'+num).src='';

    if(width == ''){
        document.getElementById('captchaCode'+num).style.width = '200px';
    }else{
        document.getElementById('captchaCode'+num).style.width = width+'px';
    }

    if(height == ''){
        document.getElementById('captchaCode'+num).style.height = '80px';
    }else{
        document.getElementById('captchaCode'+num).style.height = height+'px';
    }

    if(num == ''){
        document.getElementById('captchaCode').src='captcha.php?'+Math.random()+extra+'&width='+width+'&height='+height;
    }else{
        document.getElementById('captchaCode'+num).src='captcha.php?'+Math.random()+'&num='+num+extra+'&width='+width+'&height='+height;
    }
}