function check()
{
    var phone = document.getElementById('phone').value;
    var mail = document.getElementById('emailD').value;
    var fio = document.getElementById('fio').value;
    var data = document.getElementById('data').value;
    var city = document.getElementById('city').value;
    var personal = document.getElementById('personal').value;
    var phone = document.getElementById('phone').value;
    var education = document.getElementById('mess_501').value;
    var opit = document.getElementById('mess_500').value;
    var message = document.getElementById('mess_200').value;

if (phone!= '') { 
if (!isNaN(phone))  { } else { alert("Неправильно указан телефон");  document.getElementById('phone').value=''; }
}

// проверка e-mail
if  ((mail!= '')) { 
 m = mail.toLowerCase();
 var filter = /([a-z0-9._-]+@[a-z0-9._-]+\.[a-z]{2,3}$)/;
 if (!filter.test(m)) { alert("Неправильно введен e-mail!"); document.getElementById('mail').value=''; } 
}
// проверка e-mail

if ((education!= '') && (opit!= '') && (message!= '') && (phone!= '') && (mail!= '') && (fio!= '') && (data!= '') && (city!= '') && (personal!= '') && (phone!= '') ) { document.iblock_add.btn.disabled = false; } else {  document.iblock_add.btn.disabled = true; }


}

function checkLength_200(){
        if( document.iblock_add.mess_200.value.length > 200 ){
                document.iblock_add.mess_200.value = document.iblock_add.mess_200.value.substring(0, 200);
        }
        document.iblock_add.mess_lenght_200.value = 200 - document.iblock_add.mess_200.value.length;
}


function checkLength_501(){
        if( document.iblock_add.mess_501.value.length > 500 ){
                document.iblock_add.mess_501.value = document.iblock_add.mess_501.value.substring(0, 500);
        }
        document.iblock_add.mess_lenght_501.value = 500 - document.iblock_add.mess_501.value.length;
}

function checkLength_500(){
        if( document.iblock_add.mess_500.value.length > 500 ){
                document.iblock_add.mess_500.value = document.iblock_add.mess_500.value.substring(0, 500);
        }
        document.iblock_add.mess_lenght_500.value = 500 - document.iblock_add.mess_500.value.length;
}