Check if character is number?

Question

I need to check whether justPrices[i].substr(commapos+2,1).

The string is something like: \"blabla,120\"

In this case it would check whether \'0

Answer 1

This seems to work:

Static binding:

String.isNumeric = function (value) {
    return !isNaN(String(value) * 1);
};

Prototype binding:

String.prototype.isNumeric = function () {
    return !isNaN(this.valueOf() * 1);
};

It will check single characters, as well as whole strings to see if they are numeric.