function check_si_form_info(form,mark,edit){
     if(mark==11 || mark=="all"){
            if(form.login.value==""){
                si_check_login.innerHTML="Please enter Login Name!";
                si_check_login.style.height="auto";
                form.login.style.backgroundColor="#FFD5FF";
                return false;
            }else if (form.login.value!==""){
            var loginname = form.login.value;
            xmlhttp=new XMLHttpRequest();
            xmlhttp.open('get','si/check_si_loginname.php?loginname='+loginname,true);
            xmlhttp.onreadystatechange = function(){
                if(xmlhttp.readyState == 4){
                    if(xmlhttp.status == 200){
                        msg2 = xmlhttp.responseText;
                        if(msg2 == '2'){
                        si_check_login.innerHTML="Login name is not available!";
                        si_check_login.style.height="auto";
                        form.login.style.backgroundColor="#FFD5FF";
                        return false;
                        }else if(msg2 == '1'){
                        si_check_login.innerHTML="";
                        si_check_login.style.height="0px";
                        form.login.style.backgroundColor="#FFFFFF";
                        }
                    }//200
                }//4
            }//onreadystatechange
            xmlhttp.send(null);
            }
            if (msg2 == '2'){
            return false;
            }
    }//11
   }

function check_si_form_info(form,mark,edit){
     var msg2;// <-- Declare a variable
     if(mark==11 || mark=="all"){
            if(form.login.value==""){
               ...
                return false;
            }else if (form.login.value!==""){
            var loginname = form.login.value;
            xmlhttp=new XMLHttpRequest();
            xmlhttp.open('get','si/check_si_loginname.php?loginname='+loginname,true);
            xmlhttp.onreadystatechange = function(){
                if(xmlhttp.readyState == 4){
                    if(xmlhttp.status == 200){
                        msg2 = xmlhttp.responseText;
                        if(msg2 == '2'){
                            ...
                            form.login.style.backgroundColor="#FFD5FF";
                            return false; // <--- false isn't received by any func
                        }else if(msg2 == '1'){
                            ...
                        }
                    }//200
                }//4
            }//onreadystatechange
            xmlhttp.send(null);
            }
            if (msg2 == '2'){ //<---This condition is always false
                return false;
            }

var msg2 ="";
function check_si_form_info(form,mark,edit){