1.Example codes
<input type="number" min="1" step="1"
onkeypress="return event.charCode >= 48 && event.charCode <= 57"
title="Numbers only" value="1">
2.
var inputBox = document.getElementById("inputBox");
var invalidChars = [
"-",
"+",
"e",
"."
];
inputBox.addEventListener("input", function() {
this.value = this.value.replace(/[e\+\-\.]/gi, "");
});
inputBox.addEventListener("keydown", function(e) {
if (invalidChars.includes(e.key)) {
e.preventDefault();
}
});