JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
<script>
</script>
</head>
<body>
<input onclick="disableSubmit()" type="button" value="wyłącz">
<input type="submit" value="wyślij">
<input type="submit" value="wyślij">
</body>
</html>

JavaScript

function disableSubmit(){
	submitb = document.querySelectorAll("input[type='submit']");
	for (var i=0; i < submitb.length; i++) {
    submitb[i].setAttribute("disabled", true);
	}
}