Keeping your child safe online is incredibly important. Always monitor your child's time online, particularly younger children. Keep the computer in a central spot in the home where it's easy to keep an eye on what your child is doing and viewing online. For mobile devices, you can set them to forget Wi-Fi passcodes so your children can not go online without you knowing.
There are links on this page to give you the tools to be able to keep your child safe whilst online.