Show height in percentage

HTML

<script>
var full = $('#wrap').height();
var value = $('#bla').height();
var percentage = value*100/full ;

$('h1').html( percentage + '%');


var inter=setInterval(function(){
    var full = $('#wrap').height();
    var value = $('#bla').height();
    var percentage = value*100/full ;
    $('h1').html( percentage + '%');
},10)
$('#bla').delay(1500).animate({
	height: '74%'
},2200, "easeOutElastic");
</script>


<div id="wrap">
<div id="bla">
    <h1 class="hitme"></h1>
</div>
</div>

CSS

#wrap{
    width:300px;
    height:500px;
    position:relative;
    padding:0;
    margin:0 auto;
}
#bla{
    width:100%;
    height:23%;
    position:relative;
    padding:0;
    margin:0;
    background:#339933;
}
#bla h1{
    position:absolute;
    top:0;
    bottom:0;
    width:100%;
    text-align:center;
    margin:auto;
    padding:0;
    display:table;
}

JavaScript

var full = $('#wrap').height();
var value = $('#bla').height();
var percentage = value*100/full ;

$('h1').html( percentage + '%');


var inter=setInterval(function(){
    var full = $('#wrap').height();
    var value = $('#bla').height();
    var percentage = value*100/full ;
    $('h1').html( percentage + '%');
},10)
$('#bla').delay(1500).animate({
	height: '74%'
},2200, "easeOutElastic");