Uncaught ReferenceError: <function> is not defined at HTMLInputElement.onclick
Your error is because you have defined your function inside:
<script type="text/javascript" src="lib.js">
the correct way is to close that script tag first like so:
<script type="text/javascript" src="lib.js"></script>
and then defining the script tag again to define the function like so:
<script>
function(){
//body of function
};
</script>
<script type="text/javascript" src="lib.js"></script>
<script>
function decryptfun() {
var pass = "hjubjbjhdgyuwj";
var encrtoken = "abcdefghijklmn";
//var p = lib.decrypt(encrtoken, atob(pass)); //USE THIS IN YOUR CASE
var p = "test"; //just for example
alert(p);
}
</script>
<h1>Decrypt Operation</h1>
<input type="button" onclick="decryptfun()" value="Click">