to find a number of unique letters in string. (Eg. if keyword is unique, Unique count will be '4')
is it correct or not?
<html>
<body>
<form name="fn">
string:<input type="text" value="" name="number1" required><br>
<input type="button" onClick=a() value="unique letter number">
</form>
<script>
var count=0;
var st="";
var t=0;var h=0;
function a(){
st=document.fn.number1.value;
alert("your enter string is " st);
for(var i=0;i<st.length;i ){
for(var j=0;j<st.length;j ){
if(st.charAt(i)==st.charAt(j)
