Simple Typing tutor

HTML

<div id='res'></div>
<div id='dynm' ></div>

CSS

.keyeater{
width:50px; height:50px;
position:absolute;
text-align:center; font-size:30px;
border-radius:50%;
box-shadow: inset 0px 10px 30px 5px rgba(255, 255, 255, 1);
line-height:65px;color:#EDF5F5;
animation: bub 2000ms infinite alternate;
}
@keyframes bub {
0%   { height:65px;width:65px; }
100% { height:50px; }
}
body{
overflow:hidden;
}
#dynm{
position:absolute;
font-family: 'Cooper Std Black';
top:0px;
left:0px;
width:100%;
height:100%;
background: #09f;
}
#res{position:absolute;
top:0;left:0;z-index:100; }

JavaScript

$(document).keypress(function(e){
    str = String.fromCharCode(e.which);
 
//alert(str.charCodeAt(0) +" : "+str+'<br>');
    $('a').each(function(elm,i){
    
        if(e.which==$(this).attr('key')){
        $(this).css({'transition-property':'transform','transition':'700ms ease-in-out'});
 $(this).css('transform','scale(2) translateY(-50px)');   
var that = this;
setTimeout(function(){
    
    $(that).remove();
    
},700);
 
       
    }
    
    });
    
    
});



setInterval(function(){
    keyarr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmonpqrstuvwxyz1234567890-=[]{} ;':\"\\|/?><.,!@#$%^&*()_+`~";
    keyarr = keyarr.split("");
    key = Math.round(Math.random()*keyarr.length);
    key = keyarr[key];
   var lft = Math.round(Math.random()*$('#dynm').width());
 var scale =(Math.random()*1.5);
 scale = parseFloat(scale).toFixed(2);
 var speed = Math.floor(Math.random() * (10000 - 5000 + 1)) + 5000;
 //  $('#res').text(speed);
 if(scale<0.80){ scale = 0.9 }
  if(lft > $('#dynm').width()-50){ lft=lft-50 }
   
        if(key){
    var keyeater = $('<a/>',{'class':'keyeater','key':key.charCodeAt(0)});
            keyeater.text(key).css({'left':lft,'top':$(window).height()+60,'transform':'scale('+scale+')'}).animate({top:-50},speed);
    $('#dynm').append(keyeater);
        }
    try{
$('a').each(function(elm,i){
    
        if($(this).position().top<-45){
        $(this).remove();
    }
    
    });
    }
    catch(e){
}   
},1000);