Prevent double submission of form using jQuery

Question

Problem:

I have a script where the user can press the keys C or M to choose an option. Once either key is pressed the form will be submitted. Since there is a strict rule that each option can be submitted once, some press multiple times.

Question:

How can I prevent users from submitting the form again after they have pressed the C or M key? I want them to be able to press either key once the page refresh after submission.

Code in PHP / jQuery:

if (in_array($checkstring, $footer))
    {
        echo '
            <script type="text/javascript">
                $(document).ready(function()
                {
                    $(window).keypress(function(e)
                    {
                        if (e.which == 99)
                        {
                            $("input#left").val( 1 );
                            $("form").submit();
                        }
                        else if (e.which == 109)
                        {
                            $("input#right").val( 1 );
                            $("form").submit();
                        }
                    });

                    '.$warning.'
                });
            </script>
        ';
    }

Answer 1

I'm thinking you are looking for something like:

which creates a Boolean variable set to false and if the variable is false and key = C|M set once to true then the function won't run submit again because once is true and not false

var once = false;
$(window).keypress(function(e){
    if(!once){
        if(e.which == 99){
            $("input#left").val( 1 );
            $("form").submit();
            once = true;
            //maybe a function to time out to reset once after x seconds?
        }else if (e.which == 109){
            $("input#right").val( 1 );
            $("form").submit();
            once = true;
            //maybe a function to time out to reset once after x seconds?
        }
    }
});

Answer 2

var once = false;
$(window).keypress(function(e){
    if(!once){
        if(e.which == 99 || e.which == 109){
            $("input#"+(e.which == 99)?"left":"right").val( 1 );
            $("form").submit();
            once = true;
        }
    }
});

Answer 3

     $(window).keypress(function(e)
    e.stopPropagation();
 /* here we apply this because when we press

 click then it takes form submit action

 so we prevent all the things when we

 press key as you mention in your code*/
                        {
                            if (e.which == 99)
                            {
                                $("input#left").val( 1 );
                                $("form").submit();
                            }
                            else if (e.which == 109)
                            {
                                $("input#right").val( 1 );
                                $("form").submit();
                            }
                        });

reference [event.stopPropagation()][1]


  [1]: http://api.jquery.com/event.stopPropagation/