Assert value is Number

isNumber.js

/**
 * Determine whether the supplied value's datatype is Number.
 * Odd problems can occur eg: "1"+"6" is "16" not 7.
 * @param {Mixed} value Could be a true number: 123, 12.00, or eg: "123", "12.00" 
 * @return {Boolean} Whether value's type is Number, eg: "123" would be false whereas 123 would be true.
 */
function isNum(data)
{  
	return !isNaN(parseFloat(data)) && typeof data !== 'string';
}