How to validate with Javascript an Input text with Hours and Minutes

Question

I have to build an HTML Form with an Input text field for Hours and Minutes.
Something like:

Name : [Foo]
Surname

Answer 1

How about

function validTime(inputStr) {
    if (!inputStr || inputStr.length<1) {return false;}
    var time = inputStr.split(':');
    return time.length === 2 
           && parseInt(time[0],10)>=0 
           && parseInt(time[0],10)<=23 
           && parseInt(time[1],10)>=0 
           && parseInt(time[1],10)<=59;
}