Consider a JavaScript method that needs to check whether a given string is in all uppercase letters. The input strings are people's names.

The current algorithm is to check for any lowercase letters.

var check1 = Jack Spratt;    

var check2 = BARBARA FOO-BAR; 

var check3 = JASON D'WIDGET;  



var isUpper1 = HasLowercaseCharacters(check1);  

var isUpper2 = HasLowercaseCharacters(check2);

var isUpper3 = HasLowercaseCharacters(check3);



function HasLowercaseCharacters(string input)

{

    //pattern for finding whether any lowercase alpha characters exist

    var allLowercase; 



    return allLowercase.test(input);

}

Is a regex the best way to go here?

What pattern would you use to determine whether a string has any lower case alpha characters?