function buy() {

        var email_uname_obj= document.getElementById("email_uname");

        if(email_uname_obj) {

            if(email_uname_obj.value.length==0) {
                alert("You need to provide your Picsean username or a valid email address. The download link for the magazine will be sent to your email address!");
                email_uname_obj.focus();
                return false;
            }
            
            //Check if email address format

            if(email_uname_obj.value.indexOf('@')==-1) {

                //Has to be a username

                check_username(email_uname_obj.value);

            }
            else {

                //Has to be an email address

                if(chkEmailFormat(email_uname_obj.value) == false) {
                    alert("You need to provide a valid email address. The download link for the magazine will be sent to your email address!");
                    email_uname_obj.focus();
                    return false;
                }
                else {
                    document.getElementById("custom_url").value= "email:"+email_uname_obj.value;
                    document.getElementById("mag_form").submit();
                }

            }

        }
	 
        return true;
}

function check_username(uname) {

   //     document.getElementById('dialog').style.display='block';
   //     document.getElementById('fade').style.display='block';


        $.ajax({
              type: 'POST',
              url: 'checkuser.php',
              data: 'username='+uname,
              success: checkUserResponse
        });
}

function checkUserResponse(data) {

        data= data.trim();

        if(data == 'OK') {
       //     document.getElementById('dialog').style.display='none';
      //      document.getElementById('fade').style.display='none';
            alert("You need to provide a valid Picsean username. The download link for the magazine will be sent to your email address!");
            document.getElementById("email_uname").focus();
            return false;
        }
        else {
            document.getElementById("custom_url").value= "uid:"+document.getElementById("email_uname").value;
            document.getElementById("mag_form").submit();
        }
}

String.prototype.trim = function () {
        return this.replace(/^\s*/, "").replace(/\s*$/, "");
    }