i just need a div to be shown when on submit of form errors arise just like yahoo login

i just need a div to be shown when on submit of form errors arise just
like yahoo login

i want the to be displayed when i didnt find any record in the databaase
<div id="error">Record not found in the database</div>
<form action="login.php" method="get">
<div id="block">
<label id="user" for="name">p</label>
<input type="text" name="username" id="name"
placeholder="Username" required/>
<label id="pass" for="password">k</label>
<input type="password" name="password" id="password"
placeholder="Password" required />
<input type="submit" id="submit" name="submit" value="a"/>
</div>
</form>`enter code here`