<Javascript> Random Password Generator (Javascript and HTML)

/*
NOTE: If you want to run this program, you can do two different things.
1.) You can open the console in your browser (Ctrl + Shift + I in Google Chrome)
    and copy this code into it.  Hit Enter, then type 'pwdGen()' (without the single quotes)
    and hit Enter again.  The program will then run.

2.) Download a code editor or IDE (I used Notepad++ to make this.  Here is the site: https://notepad-plus-plus.org/)
    Download or copy in both this code and another of my Pastebins entitled '<HTML> Random Password Generator (Javascript and HTML)'
    into separate documents.  I have instructions for linking them together on my HTML.
    After everything is linked, click on the 'Run' drop-down menu and click on whichever browser you want to do.
    Then all you need to do is click the button, and the program will run.
*/


function pwdGen () {    //Defines a new function that is run using the button in the HTML section

    var alpha = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';   //Three lists that have all the characters that my password generator can use
    var numb = '1234567890';
    var punc = "`~!@#$%^&*()_+-=}{[];'\":,./<>?\|";

    var possibleChars = alpha + numb;    //Combines the alpha and numb strings above

    function nextChar(chars) {    //Defines a new function that will randomly select characters from the strings
        var loc = Math.round(Math.random()*chars.length - 1);

        /*Creates a variable loc and gives it the value of a random number
         (look Math.random() and Math.round() up on your own) which is multiplied
         by the length of the string (created by combining the original strings)*/

        return chars.substring(loc, loc + 1);   //uses the number in loc to take one character out of the combined strings
    };

    /*Makes a pop-up to ask if the user wants to use the program*/
    permissionRandGen = confirm('Would you like a random password suggestion?');


    if (permissionRandGen == true) {    //If the user wants to use the program, this starts to generate the function
        var lenPwd = prompt('How long do you want your password?');   //Asks for length of the password
        var usePunc = confirm('Do you want punctuation in your password?');    //Asks the user if they want characters

        /*If the user want punctuation, adds it to the possible characters*/
        if (usePunc == true) {
            possibleChars = possibleChars + punc;
        };

        /*If the length is between 1 and 25, the program will run*/
        if (lenPwd > 0 && lenPwd < 26) {
            var newPwd = "";    //Creates a variable the will store the password

            /*Creates new characters until the password it complete*/
            for (var i = 0; i < lenPwd; i++) {
                newPwd += nextChar(possibleChars);
            };

        /*Creates a new element in the HTML section, adds text to it, and then adds the element to <body>*/
        /*Shows the user their new password suggestion*/
        var docElementNewPwd = document.createElement("p")
        var docTextNewPwd = document.createTextNode("Your new password is: " + newPwd);
        docElementNewPwd.appendChild(docTextNewPwd);
        document.body.appendChild(docElementNewPwd);
        /*NOTE: If the program is run multiple times without refreshing the page, you will be able to see all of the passwords generated*/

        /*If the password length is longer or shorter than the limit, this informs the user*/
        } else {
            var dELenError = document.createElement("p");
            var dTLenError = document.createTextNode("I can only generate passwords between 1 and 25 characters long.");
            dELenError.appendChild(dTLenError);
            document.body.appendChild(dELenError);
        };

    /*If the user chooses not to run the program, this creates a heading (<h2>) element to ask a rhetorical question*/
    } else {
        var dEUserEnd = document.createElement("h2");
        var dTUserEnd = document.createTextNode("Well then, why did you run me?");
        dEUserEnd.appendChild(dTUserEnd);
        document.body.appendChild(dEUserEnd);
    };
};