Internet is one of the best functions that children prefer to use in a mobile phone or computer because of many good thing. However, some people think if children use the Internet all the time, it will have disadvantages and bad things more than advantages for several reasons. Spending times on the Internet make the children do not focus on their studies because most children use the Internet to communicate or play games. If children use the Internet during class time, It will make them do not intend to study. It makes learning them worse and affect their future. Moreover, it will affect the children's bodies because most children are using the Internet in the smartphone. Using the phone for a long time, it was affecting their eyes. It caused problems with vision, such as blurred vision and dry eyes. To sum up, it is better if children use the Internet appropriately because if children use the Internet too much, it will provide many disadvantages them.