How to prevent status aborted to be happening

Question

Hello dear programmers . i am developing an online mmorpg game . so speed is very important . i have a complex map system which is coded by me . at this map system for walking i am using ajax .

using iis 7.5 and netframework 3.5 .

at this page you can use w,a,s,d or keyboard arrow keys for walking

http:// www.pokemoncraft.com/gamepage.aspx ( username : test1234 , password : test1234 )

as you can see at image below when a player pushes the movement buttons faster ( without waiting to move completed ) status being aborted so it really prevents walking faster

i want to prevent this is from happening ( disable buttons to be pushed so fast until post event completed )

http://img716.imageshack.us/img716/2168/abortedd.png

these values obtained with firefox - firebug

here what happens when you push keyword buttons for moving

i appreciate any help thank you

<script type="text/javascript">

 document.onkeydown = cancelArrowKeys;

 function cancelArrowKeys(e) {
     try {
         var e = window.event || e


         var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;


         if (key == 37 || key == 38 || key == 39 || key == 40 || key == 13 || key==65 || key==87 || key==68 || key==83) {
             if (key == 13)
                 document.getElementById('<%=btnFightPokemon.ClientID%>').click();

             if (key == 37 || key == 65) 
             {
                 document.getElementById('<%=btnHiddenWest.ClientID%>').click();
             }

             if (key == 38 || key == 87) 
             {
                 document.getElementById('<%=btnHiddenNorth.ClientID%>').click();
             }

             if (key == 39 || key == 68) 
             {
                 document.getElementById('<%=btnHiddenEast.ClientID%>').click();
             }

             if (key == 40 || key == 83) 
             {
                 document.getElementById('<%=btnHiddenSouth.ClientID%>').click();
             }

             event.returnValue = false;
        }
    }
     catch (Exception) {
         return false;
     }

 }

 var k = 0;

 function moveLeft() {
     try {
         document.getElementById('<%=btnHiddenWestMulti.ClientID%>').click();
     }
     catch (Exception) {
         return false;
     }
 }

 function moveRight() {   
     try {
         document.getElementById('<%=btnHiddenEastMulti.ClientID%>').click();
     }
     catch (Exception) {
         return false;
     }       
     }

     function moveUp() {    
     try {
         document.getElementById('<%=btnHiddenNorthMulti.ClientID%>').click();
     }
     catch (Exception) {
         return false;
     }
 }

 function moveDown() {
     try {
         document.getElementById('<%=btnHiddenSouthMulti.ClientID%>').click();
     }
     catch (Exception) {
         return false;
     }
 }