I'm trying to learn some javascript and i'm having trouble figuring out why my code is incorrect (i'm sure i'm doing something wrong lol), but anyways I am trying to create a login page so that when the form is submitted javascript will call a function that checks if the login is in a mysql database and then checks the validity of the password for the user if they exist. however I am getting an error (Illegally Formed XML Syntax) i cannot resolve. I'm really confused, mostly because netbeans is saying it is a xml syntax error and i'm not using xml. here is the code in question:

function validateLogin(login){

  login.addEventListener("input", function() {
    $value = login.value;
    if (<?php
    //connect to mysql
    mysql_connect(host, user, pass) or die(mysql_error());
    echo("<script type='text/javascript'>");
    echo("alert('MYSQL Connected.');");
    echo("</script>");
    //select db
    mysql_select_db() or die(mysql_error());
    echo("<script type='text/javascript'>");
    echo("alert('MYSQL Database Selected.');");
    echo("</script>");
    //query
    $result = mysql_query("SELECT * FROM logins") or die(mysql_error()); 
    //check results against given login
    while($row = mysql_fetch_array($result)){
      if($row[login] == $value){
        echo("true");
        exit(0);
      }
    }
    echo("false");
    exit(0);
      ?>) {
      login.setCustomValidity("Invalid Login. Please Click 'Register' Below.")
    } else {
      login.setCustomValidity("")
    }

  });
}

the code is in an external js file and the error throws on the last line. Also from reading i understand best practices is to not mix js and php so how would i got about separating them but maintaining the functionality i need? thanks!