How to make an input only accept numbers Binary input type="text" name="number" / [closed]

function SomenteNumero(e){
 var tecla=(window.event)?event.keyCode:e.which;
if((tecla==48 || tecla==49)) return true;
 else{
return false;
 }
 }

<input type="text" size="10" value=""' onkeypress="return SomenteNumero(event);">

• A function is a JavaScript procedure - an instruction set that executes a task or calculates a value. To use a function, you must define it somewhere in the scope of which you want to call it.
• The onkeypress event occurs when the user presses a key (on the keyboard) - in this case, calls the function.
• keyCode (Keyboard Codes): Represents the key number that the user presses on the keyboard 48 is zero and 49 is the one.
• If (if) the key is zero or one, fine, accept (return true)
• else (else) does not accept.

  

I noticed that keyCode is now obsolete and will be discarded:

I tested with e.key

function SomenteNumero(e){
 var tecla=(window.event)?e.key:e.which;
if((tecla==48 || tecla==49)) return true;
 else{
return false;
 }
 }

<input type="text" size="70" value=""' onkeypress="return SomenteNumero(event);">

in modern browsers.