JQuery to allow only numeric input in text box using key code

Question

I am trying to allow only numbers [0-9] to be typed in a text box. If an alpha or special character is typed, I do not want it to be shown in the text box. Currently my code is as follows:

$('#TEXTBOX').on("keydown", function(event){
    var keyCode = event.which;
    if(!((keyCode > 47 && keyCode < 58) ||  (keyCode > 95 && keyCode < 106) ||  keyCode == 08)){
        event.preventDefault();
    }
});

I am having a few problems.

1. This function is still allows special characters [i.e (SHIFT + 1) gives !, (SHIFT + 2) gives @] I do not want these key combinations to allow insert into text box

2. I am using magic numbers. I would prefer not to use magic numbers and logic but this is the only way I was able to get the input validation to work.... are there any suggestions on other methods?

My main concern is my first problem with the special characters.

Answer 1

$('#TEXTBOX').on("keydown", function(event){
    var keyCode = event.which;
    var charCode = (event.charCode) ? event.charCode : ((event.keyCode) ? event.keyCode: ((event.which) ?   evt.which : 0));
    var char = String.fromCharCode(charCode);
    var re = new RegExp("[0-9]", "i");
    if (!re.test(char)) 
    {
         event.preventDefault(); 
    }
});

Answer 2

Use as

$('#TEXTBOX').on("keydown", function(event){
    if(event.shiftKey)
         return false;
    var keyCode = event.which;
    if(!((keyCode > 47 && keyCode < 58) ||  (keyCode > 95 && keyCode < 106) ||  keyCode == 08)){
        event.preventDefault();
    }
});

Answer 3

$(document).ready(function() {
    $("#txtboxToFilter").keydown(function (e) {
        // Allow: backspace, delete, tab, escape, enter and .
        if ($.inArray(e.keyCode, [46, 8, 9, 27, 13, 110, 190]) !== -1 ||
             // Allow: Ctrl+A
            (e.keyCode == 65 && e.ctrlKey === true) || 
             // Allow: home, end, left, right, down, up
            (e.keyCode >= 35 && e.keyCode <= 40)) {
             // let it happen, don't do anything
                 return;
        }
        // Ensure that it is a number and stop the keypress
        if ((e.shiftKey || (e.keyCode < 48 || e.keyCode > 57)) && (e.keyCode < 96 || e.keyCode > 105)) {
            e.preventDefault();
        }
    });
});

Answer 4

Worked For me (Only Numbers are allowed)

            var key = e.charCode || e.keyCode || 0;

            alert(key);

            if (key < 48 || key > 58)
                return false;