php input form can only be numbers not words - php

Question

i made a form where you can put a number and show which one is the highest.
i want to make sure you can put any words in this form.
that there show a notification you cant put words in the form
<?php
function maxGetal($getal1, $getal2)
{
if ($getal1 > $getal2) {
return ($getal1);
} elseif ($getal2 > $getal1) {
return ($getal2);
} else {
return ("gelijk");
}
}
?>
<form action="" method="post">
<input type="text" name="eerstegetal" placeholder="Eerste getal"><br>
<input type="text" name="tweedegetal" placeholder="Tweede getal"><br>
<input type="submit" name="submit" value="Bereken hoogste getal">
<p> -----------------------------------------------------------------------</p>
</form>
<?php
if (isset($_POST["submit"])) {
$maxgetal = maxGetal($_POST["eerstegetal"], $_POST["tweedegetal"]);
echo $maxgetal;
}
$input1 = doubleval($_POST["eerstegetal"]);
$input2 = doubleval($_POST["tweedegetal"]);
?>

Answer 1

The following code shows a notification when a letter is typed.
<?php
function maxGetal($getal1, $getal2)
{
if ($getal1 > $getal2) {
return ($getal1);
} elseif ($getal2 > $getal1) {
return ($getal2);
} else {
return ("gelijk");
}
}
?>
<form action="" method="post">
<input type="text" id="eerstegetal" name="eerstegetal" oninput="Eerste_check()" placeholder="Eerste getal"><br>
<input type="text" id="tweedegetal" name="tweedegetal" oninput="Tweede_check()" placeholder="Tweede getal"><br>
<input type="submit" name="submit" value="Bereken hoogste getal">
<p> -----------------------------------------------------------------------</p>
</form>
<?php
if (isset($_POST["submit"])) {
$maxgetal = maxGetal($_POST["eerstegetal"], $_POST["tweedegetal"]);
echo $maxgetal;
}
$input1 = doubleval($_POST["eerstegetal"]);
$input2 = doubleval($_POST["tweedegetal"]);
?>
<script src="https://code.jquery.com/jquery-3.6.1.min.js"></script>
<script>
function Eerste_check(){
var eerstegetal = $('#eerstegetal').val()
var pattern = /^\d+\.?\d*$/;
if(!pattern.test(eerstegetal)){
alert('Eerstegetal should contain only numbers.')
}
}
function Tweede_check(){
var tweedegetal = $('#eerstegetal').val()
var pattern = /^\d+\.?\d*$/;
if(!pattern.test(tweedegetal)){
alert('Tweedegetal should contain only numbers.')
}
}
</script>

Answer 2

Try the following:
<input type="number" name="eerstegetal" placeholder="Eerste getal"><br>
<input type="number" name="tweedegetal" placeholder="Tweede getal"><br>
I hope it helps