Have a look at this
<html>
<head>
<script type="text/javascript">
function compare () {
var one = document.getElementById('one');
var two = document.getElementById('two');
if ( one.value.substring(0,1) == two.value.substring(0,1) ) {
alert( 'same letter, same case' );
} else if ( one.value.substring(0,1).toLowerCase() ==
two.value.substring(0,1).toLowerCase() ) {
alert( 'same letter, different case' );
} else {
alert( 'different letters' );
}
}
</script>
</head>
<body>
<form onsubmit="compare()">
<input id="one" type="text" />
<input id="two" type="text" />
<input type="submit" />
</form>
</body>
</html>
Hope it helps
Unsolved 
