$(document).ready(function() {
    var predvolba = $('#predvolbaEditace').val();
    $(function() {
        $('#predvolbaEditace').keydown(function() {
            predvolba = $('#predvolbaEditace').val();
            console.log(predvolba);
        });
        console.log(predvolba);
        if (predvolba == "") {
            $('#predvolbaEditace').focus(function() {
                $(this).val("+ ");
            });
            $('#predvolbaEditace').blur(function() {
                $(this).val("");
            });
        }
    })
    $("#predvolbaEditace").keydown(function(event) {
        console.log(this.selectionStart);
        console.log(event);
        if (event.keyCode == 8) {
            this.selectionStart--;
        }
        if (this.selectionStart < 2) {
            this.selectionStart = 2;
            console.log(this.selectionStart);
            event.preventDefault();
        }
    });
});