Some times for new beginners of jQuery faces problem regarding jQuery that's not working, as I'd faced it many years ago and some of people asked me that question. So here are the some of the solutions regarding this problem:
1. Make sure jQuery library is properly linked with your web page
2. Sometimes linking multiple jQuery files (such as different versions of jQuery) may also cause problem in working properly
3. Make sure you are not having any syntax error, such as missing brackets or have extra brackets
4. Try different browsers
5. Clear browser's cache from setting option or you may use short cut (ctrl+f5) to clear cache
Hope it may help you out regarding jQuery problem.
