获取键盘数字键中符号的javascript键盘代码

Question

What is the javascript keycode for the / (forward slash) symbol regardless the language and culture of keyboard and OS? In an English keyboard the forward slash is in a key separate from the numeric keys and it's keycode is 191. However in a Spanish keyboard that character is together with the number 7 in the same key and to type it in I have to do SHIFT + 7, but that combination does not result in keycode 191!

I've tried if (event.shiftKey && event.keyCode == 55) {} where 55 is the keycode of character 7 and it works, but with an English keyboard the if (event.shiftKey && event.keyCode == 55) {} condition allows me to type in the & (ampersand) symbol.

I have a textbox in my web page for which I only want to allow users to type in digits and forward slash regardless the language of the keyboards or OSs they are using and regardless the have to press just one key to enter the forward slash or they have to do a combination of SHIFT + a numeric key or another type of combination. How can I do this?

Answer 1

As an alternative to preventing the keypress:

<textarea oninput="validate(this,/([^\/\d])/g)" ></textarea>
<script>
function validate(inp,reg)
{
    //([^\/\d]) translates to:
    //"remove everything that is not a / or a number"
    var s = inp.selectionStart;
    inp.value = inp.value.replace(reg,"");
    inp.selectionStart = s;inp.selectionEnd = s;//reset caret position
}
</script>

Answer 2

You can achieve this by listening to keypress instead of keydown, this will give you an event object that contains the actual key pressed and the corresponding ASCII code.

// Vanilla JavaScript
document.body.addEventListener('keypress', function(event) { 
  console.log(event);     
});

// jQuery
$('body').on('keypress', function (event) {
  console.log(event);
};