External javascript is not working in android?

I created a simple webpage contains two input fields and created a javascript (valid.js) for form validation on client-side and linked it to my web page. It's working fine on pc but on android browsers like UC browser and opera mini it's not working. But when i use same javascript embedded in html document it's working. I don't want to mix javascript and html. Please help me, Thank you,. (also i visited other websites(www.w3schools.com and gmail sign-up page) using UC browser and opera mini and I found javascript is on and working.)