String.prototype.isNumeric

@Description: Checks to see if a string is numeric (a float or number)
@File: String/prototype/isNumeric.js
@Author: Paul Visco
@Version: 1.1 11/27/07
@Return: Boolean True if the the string represnts numeric data, false otherwise
@Example:

var str = '12';

var answer = str.isNumeric();
//answer = true