<html>
<head>
<title>frequency</title>
<script>
var arr = [1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4, 5, 2, 5,1, 1, 2, 19, 2, 19, 4];
var a = [], b = [], prev;
arr.sort();
for ( var i = 0; i < arr.length; i++ ) {
if ( arr[i] !== prev ) {
a.push(arr[i]);
b.push(1);
} else {
b[b.length-1]++;
}
prev = arr[i];
}
var result = [a, b];
console.log(result);
document.write('[' + result[0] + ']<br>[' + result[1] + ']')
</script>
</head>
<body>
</body>
</html>
