function GetIC() {
    plaintext = document.getElementById("p").value.toLowerCase().replace(/[^a-z]/g, "");
    var counts = new Array(26);
    var totcount=0;
    for(i=0; i<26; i++) counts[i] = 0;
    for(i=0; i<plaintext.length; i++){
        counts[plaintext.charCodeAt(i) - 97]++;
        totcount++;
    }
    var sum = 0;
    for(i=0; i<26; i++) sum = sum + counts[i]*(counts[i]-1);
    ic = sum / (totcount*(totcount-1));
    document.getElementById("ic").value = ic;
    document.getElementById("count").value = totcount;
}