function load(){
document.getElementById("abonoK").style.display="none";
document.getElementById("tcK").style.display="none";
document.getElementById("emailK").style.display="none";
}

function tckont(tcno) 
{ 
var toplam,dogruMu; 
toplam = Number(tcno.substring(0,1)) + Number(tcno.substring(1,2)) + Number(tcno.substring(2,3)) + Number(tcno.substring(3,4)) + Number(tcno.substring(4,5)) + Number(tcno.substring(5,6)) + Number(tcno.substring(6,7)) + Number(tcno.substring(7,8)) + Number(tcno.substring(8,9)) + Number(tcno.substring(9,10)); 
strtoplam = String(toplam); 
onunbirlerbas = strtoplam.substring(strtoplam.length, strtoplam.length-1); 
if(onunbirlerbas != tcno.substring(10,11)) 
{ 
return dogruMu = false;
} 
return dogruMu = true; 
} 

function form_kont(){
var ony=true;
var aboneno = document.getElementById("abono");
var tcno = document.getElementById("tcno");
var email = document.getElementById("email");
var emailRegExp = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.([a-z]){2,4})$/;
	if(aboneno.value==0) { document.getElementById("abonoK").style.display="block"; ony=false; }
	else {document.getElementById("abonoK").style.display="none";}

	if(!tckont(tcno.value)) { document.getElementById("tcK").style.display="block";  ony=false; }	
	else {document.getElementById("tcK").style.display="none";}

    if(!emailRegExp.test(email.value)) {document.getElementById("emailK").style.display="block"; ony=false; }
	else {document.getElementById("emailK").style.display="none";}

	return ony;
}



function onyNm(myfield, e, dec) {
  var key;
  var keychar;

  if (window.event)
    key = window.event.keyCode;
  else if (e)
    key = e.which;
  else
    return true;
  keychar = String.fromCharCode(key);

  // numbers
  if ((("0123456789").indexOf(keychar) > -1))
    return true;

  // decimal point jump
  else if (dec && (keychar == ".")) {
    myfield.form.elements[dec].focus();
    return false;
  } else
    return false;
}

 function check_email(email_id){

                 emailRegExp = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.([a-z]){2,4})$/;
                
					 if(emailRegExp.test(document.getElementById(email_id).value))    {return true;}

	                 else{document.getElementById("eposta").style.display="block";	   return false;}
}