<form id="myform" action="login.php" method="post">
 Username : <input type="text" name="username" minlength="4" required/>
 Password : <input type="password" name="password" minlength="8" required />
 <input type="submit" name="submit" id="submit" value="Log In"/>

I have a rather "weird" problem with Mozilla web browser. I created a website which contains many basic forms, built with HTML5 (for example : simple login form, which asks for a user's login and password). It's a very simple and basic login form; it is submitted when the user clicks the "submit" button. Here is the code : <form id="myform" action="login.php" method="post"> Username : <input type="text" name="username" minlength="4" required/> Password : <input type="password" name="password" minlength="8" required /> <input type="submit" name="submit" id="submit" value="Log In"/> The problem I am having is with Mozilla Firefox browser. My form works with EVERY browser out there : Chrome, Safari, Opera, IE, etc When I open the form in other browsers, the cursor is blinking in the "Username" field, of course. As it should be. But, when I open this form in Mozilla, there is no cursor blinking. I cannot write anything in the username or password fields. (It is as though the fields have been DISABLED, or set to READ-ONLY) But, when I click on the "Log In" button, then an error-alert message pops up, saying : "Username is a required field" (obviously). Then --- and only then --- the cursor finally appears in the Username text-box, and I am able to provide the login credentials. I find this rather amusing. But, it certainly won't be amusing to someone who is trying to log into my website with Mozilla Firefox! What could the problem be? I know there is nothing wrong with my code, because the form works in ALL browsers. It even works in Mozilla, too...........but only AFTER I have clicked on the "submit" button, and then I am prompted to input the login credentials.