Validating Hour Of The Day Is Numeric And Less Than 24 And Bigger Than 0?

The code bellow validates an number is between 0 and 59.I want to modify the code to make another function which validates an entered value is numeric and between 0 and 24 (for the hour of the day).Since sorry i did not understand the function bellow, can some one pls help me understand it or guide me for creating a similar function which validates the entered hour of the day is between 0 and 24?

function isBetween_0_59(evt, ctrl) {
var result = isNumberKey(evt);
if (result) {[code]........