jquery keyup function check if number

Question

i am trying to create an input field where the user can only type in numbers. this function is already working almost fine for me:

        $(\'#p_first\').k         


        

Answer 1

I used the following function to check if a given string is number or not. This implementation works on keyup and keydown and also takes care of numpad keys

// Validate Numeric inputs
function isNumber(o) {
    return o == '' || !isNaN(o - 0);
}

Assuming that your key code on the keyup or keydown event is in keyCode variable:

var keyCode = e.keyCode || e.which;
if (keyCode >= 96 && keyCode <= 105) {
        // Numpad keys
        keyCode -= 48;
}
console.log(isNumber(String.fromCharCode(keyCode)));
console.log(isNumber($(this).val() + String.fromCharCode(keyCode)));

Return false if the return value from isNumber is false:

    var txtVal = $(this).val() + String.fromCharCode(keyCode);
    if (!isNumber(txtVal)) {
        e.returnValue = false;
    }