How to restrict just numbers input in input number in Firefox?

Question

In Firefox you can enter letters, they show in the screen but not in the js code, about the value. I would like just restrict that the user can put in letters in the input field. Just restrict it to numbers.

https://jsfiddle.net/j5fv4htp/1/

  <input step="0.1" class="number" name="SupplyAirFlow" value="" pattern=".{1,}" type="number">


document.querySelector("input.number").onkeydown = function() {
        console.log("value: ", this.value); 
}; 

Answer 1

If you want only numbers in the input use:

document.getElementsByClassName('number')[0].addEventListener('keydown', function(e) {
    var key   = e.keyCode ? e.keyCode : e.which;

    if (!( [8, 9, 13, 27, 46, 110, 190].indexOf(key) !== -1 ||
         (key == 65 && ( e.ctrlKey || e.metaKey  ) ) || 
         (key >= 35 && key <= 40) ||
         (key >= 48 && key <= 57 && !(e.shiftKey || e.altKey)) ||
         (key >= 96 && key <= 105)
       )) e.preventDefault();
});