Javascript String isNullOrWhitespace(str)

/**//ww  w.  j a  v  a 2s . c o m
 * Checks if the string is empty, whitespace or null
 * 
 * str: String to check
 */
String.isNullOrWhitespace = function(str) {
    if (str === undefined || str === null) {
        return true;
    }
    
    return str.toString().isNullOrWhitespace();
}